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.MuiPaper-root{border-radius:6px;margin-top:8px;min-width:268px;color:rgb(55, 65, 81);box-shadow:rgb(255, 255, 255) 0px 0px 0px 0px,rgba(0, 0, 0, 0.05) 0px 0px 0px 1px,rgba(0, 0, 0, 0.1) 0px 10px 15px -3px,rgba(0, 0, 0, 0.05) 0px 4px 6px -2px;}.css-oe3wem .MuiPaper-root .MuiMenu-list{padding:4px 0;}.css-oe3wem .MuiPaper-root .MuiMenuItem-root .MuiSvgIcon-root{font-size:18px;color:rgba(0, 0, 0, 0.6);margin-right:12px;}.css-oe3wem .MuiPaper-root .MuiMenuItem-root:active{background-color:rgba(25, 118, 210, 0.08);}</style><style data-emotion="css 12mehxg">.css-12mehxg{padding:0;margin:0;list-style:none;outline:0;}</style><ul role="tree" id="left-nav-treeview" aria-multiselectable="false" class="MuiTreeView-root css-12mehxg" tabindex="0" aria-label="left navigation"><style data-emotion="css 1gesgke">.css-1gesgke .MuiTreeItem-content{color:#282a36;border-radius:4px;}.css-1gesgke .MuiTreeItem-content:hover{background-color:#f9f9f9;}.css-1gesgke .MuiTreeItem-content.Mui-selected,.css-1gesgke .MuiTreeItem-content.Mui-selected.Mui-focused{background-color:var(--tree-view-bg-color, #EAF6FB);color:var(--tree-view-color, #0A85C2);}.css-1gesgke .MuiTreeItem-content.Mui-selected svg.MuiTreeItem-ChevronRightIcon,.css-1gesgke .MuiTreeItem-content.Mui-selected.Mui-focused svg.MuiTreeItem-ChevronRightIcon{fill:var(--tree-view-color, #0A85C2);}.css-1gesgke .MuiTreeItem-content.Mui-focused{background-color:#f9f9f9;}.css-1gesgke .MuiTreeItem-content .MuiTreeItem-label{font-weight:inherit;color:inherit;}.css-1gesgke .MuiTreeItem-content .MuiTreeItem-iconContainer{;}.css-1gesgke .MuiTreeItem-group{margin-left:0;}.css-1gesgke .MuiTreeItem-group .MuiTreeItem-content{padding-left:16px;}</style><style data-emotion="css 1oy5rnm">.css-1oy5rnm{list-style:none;margin:0;padding:0;outline:0;}.css-1oy5rnm .MuiTreeItem-content{color:#282a36;border-radius:4px;}.css-1oy5rnm .MuiTreeItem-content:hover{background-color:#f9f9f9;}.css-1oy5rnm .MuiTreeItem-content.Mui-selected,.css-1oy5rnm .MuiTreeItem-content.Mui-selected.Mui-focused{background-color:var(--tree-view-bg-color, #EAF6FB);color:var(--tree-view-color, #0A85C2);}.css-1oy5rnm .MuiTreeItem-content.Mui-selected svg.MuiTreeItem-ChevronRightIcon,.css-1oy5rnm .MuiTreeItem-content.Mui-selected.Mui-focused svg.MuiTreeItem-ChevronRightIcon{fill:var(--tree-view-color, #0A85C2);}.css-1oy5rnm .MuiTreeItem-content.Mui-focused{background-color:#f9f9f9;}.css-1oy5rnm .MuiTreeItem-content .MuiTreeItem-label{font-weight:inherit;color:inherit;}.css-1oy5rnm .MuiTreeItem-content .MuiTreeItem-iconContainer{;}.css-1oy5rnm .MuiTreeItem-group{margin-left:0;}.css-1oy5rnm .MuiTreeItem-group .MuiTreeItem-content{padding-left:16px;}</style><li class="MuiTreeItem-root css-1oy5rnm" role="treeitem" id="left-nav-treeview-0-0" tabindex="-1" style="margin-top:0.1875rem;margin-bottom:0.1875rem"><style data-emotion="css khel7y">.css-khel7y{padding:0 8px;width:100%;display:-webkit-box;display:-webkit-flex;display:-ms-flexbox;display:flex;-webkit-align-items:center;-webkit-box-align:center;-ms-flex-align:center;align-items:center;cursor:pointer;-webkit-tap-highlight-color:transparent;}.css-khel7y:hover{background-color:rgba(0, 0, 0, 0.04);}@media (hover: none){.css-khel7y:hover{background-color:transparent;}}.css-khel7y.Mui-disabled{opacity:0.38;background-color:transparent;}.css-khel7y.Mui-focused{background-color:rgba(0, 0, 0, 0.12);}.css-khel7y.Mui-selected{background-color:rgba(25, 118, 210, 0.08);}.css-khel7y.Mui-selected:hover{background-color:rgba(25, 118, 210, 0.12);}@media (hover: none){.css-khel7y.Mui-selected:hover{background-color:rgba(25, 118, 210, 0.08);}}.css-khel7y.Mui-selected.Mui-focused{background-color:rgba(25, 118, 210, 0.2);}.css-khel7y .MuiTreeItem-iconContainer{margin-right:4px;width:15px;display:-webkit-box;display:-webkit-flex;display:-ms-flexbox;display:flex;-webkit-flex-shrink:0;-ms-flex-negative:0;flex-shrink:0;-webkit-box-pack:center;-ms-flex-pack:center;-webkit-justify-content:center;justify-content:center;}.css-khel7y .MuiTreeItem-iconContainer svg{font-size:18px;}.css-khel7y .MuiTreeItem-label{width:100%;min-width:0;padding-left:4px;position:relative;font-size:1rem;line-height:1.5rem;font-family:"Helvetica Neue","sans-serif";font-weight:400;font-style:normal;color:#666666;}</style><div class="css-khel7y MuiTreeItem-content" style="width:inherit"><div class="MuiTreeItem-iconContainer"/><div class="MuiTreeItem-label"><style data-emotion="css znl8a3">.css-znl8a3{display:-webkit-box;display:-webkit-flex;display:-ms-flexbox;display:flex;-webkit-flex-direction:row;-ms-flex-direction:row;flex-direction:row;min-height:1.75rem;-webkit-align-items:center;-webkit-box-align:center;-ms-flex-align:center;align-items:center;padding-left:0rem;padding-top:0.25rem;padding-bottom:0.25rem;}</style><div class="css-znl8a3"><style data-emotion="css tx8jsd">.css-tx8jsd{margin:0;font-size:1rem;line-height:1.5rem;font-family:"Helvetica Neue","sans-serif";font-weight:400;font-style:normal;color:#666666;}</style><a class="MuiTypography-root MuiTypography-body1 css-tx8jsd" target="_blank" href="https://docs.pingcap.com/zh" style="text-decoration:none;width:100%;color:inherit"><style data-emotion="css 8atqhb">.css-8atqhb{width:100%;}</style><div class="MuiBox-root css-8atqhb"><style data-emotion="css 1hwyipb">.css-1hwyipb{margin:0;font-size:1rem;line-height:1.5rem;font-family:"Helvetica Neue","sans-serif";font-weight:400;font-style:normal;color:#666666;color:inherit;font-size:0.875rem;line-height:1.25rem;}</style><div class="MuiTypography-root MuiTypography-body1 css-1hwyipb">文档中心</div></div></a></div></div></div></li><li class="MuiTreeItem-root css-1oy5rnm" role="treeitem" aria-expanded="false" id="left-nav-treeview-0-1" tabindex="-1" style="margin-top:0.1875rem;margin-bottom:0.1875rem"><div class="css-khel7y MuiTreeItem-content" style="width:inherit"><div class="MuiTreeItem-iconContainer"/><div class="MuiTreeItem-label"><div class="css-znl8a3"><div class="MuiBox-root css-8atqhb"><div class="MuiTypography-root MuiTypography-body1 css-1hwyipb">关于 TiDB</div></div><style data-emotion="css xjq79n">.css-xjq79n{-webkit-user-select:none;-moz-user-select:none;-ms-user-select:none;user-select:none;width:1em;height:1em;display:inline-block;fill:currentColor;-webkit-flex-shrink:0;-ms-flex-negative:0;flex-shrink:0;-webkit-transition:fill 200ms cubic-bezier(0.4, 0, 0.2, 1) 0ms;transition:fill 200ms cubic-bezier(0.4, 0, 0.2, 1) 0ms;font-size:1.5rem;fill:#999999;height:1rem;width:1rem;margin-left:auto;-webkit-transform:none;-moz-transform:none;-ms-transform:none;transform:none;}</style><svg class="MuiSvgIcon-root MuiSvgIcon-fontSizeMedium MuiTreeItem-ChevronRightIcon css-xjq79n" focusable="false" aria-hidden="true" viewbox="0 0 24 24" data-testid="ChevronRightIcon"><path d="M10 6 8.59 7.41 13.17 12l-4.58 4.59L10 18l6-6z"/></svg></div></div></div><style data-emotion="css 1jozaee">.css-1jozaee{margin:0;padding:0;margin-left:17px;}</style></li><li class="MuiTreeItem-root css-1oy5rnm" role="treeitem" aria-expanded="false" id="left-nav-treeview-0-2" tabindex="-1" style="margin-top:0.1875rem;margin-bottom:0.1875rem"><div class="css-khel7y MuiTreeItem-content" style="width:inherit"><div class="MuiTreeItem-iconContainer"/><div class="MuiTreeItem-label"><div class="css-znl8a3"><div class="MuiBox-root css-8atqhb"><div class="MuiTypography-root MuiTypography-body1 css-1hwyipb">快速上手</div></div><svg class="MuiSvgIcon-root MuiSvgIcon-fontSizeMedium MuiTreeItem-ChevronRightIcon css-xjq79n" focusable="false" aria-hidden="true" viewbox="0 0 24 24" data-testid="ChevronRightIcon"><path d="M10 6 8.59 7.41 13.17 12l-4.58 4.59L10 18l6-6z"/></svg></div></div></div></li><li class="MuiTreeItem-root css-1oy5rnm" role="treeitem" aria-expanded="false" id="left-nav-treeview-0-3" tabindex="-1" style="margin-top:0.1875rem;margin-bottom:0.1875rem"><div class="css-khel7y MuiTreeItem-content" style="width:inherit"><div class="MuiTreeItem-iconContainer"/><div class="MuiTreeItem-label"><div class="css-znl8a3"><div class="MuiBox-root css-8atqhb"><div class="MuiTypography-root MuiTypography-body1 css-1hwyipb">应用开发</div></div><svg class="MuiSvgIcon-root MuiSvgIcon-fontSizeMedium MuiTreeItem-ChevronRightIcon css-xjq79n" focusable="false" aria-hidden="true" viewbox="0 0 24 24" data-testid="ChevronRightIcon"><path d="M10 6 8.59 7.41 13.17 12l-4.58 4.59L10 18l6-6z"/></svg></div></div></div></li><li class="MuiTreeItem-root css-1oy5rnm" role="treeitem" aria-expanded="false" id="left-nav-treeview-0-4" tabindex="-1" style="margin-top:0.1875rem;margin-bottom:0.1875rem"><div class="css-khel7y MuiTreeItem-content" style="width:inherit"><div class="MuiTreeItem-iconContainer"/><div class="MuiTreeItem-label"><div class="css-znl8a3"><div class="MuiBox-root css-8atqhb"><div class="MuiTypography-root MuiTypography-body1 css-1hwyipb">部署标准集群</div></div><svg class="MuiSvgIcon-root MuiSvgIcon-fontSizeMedium MuiTreeItem-ChevronRightIcon css-xjq79n" focusable="false" aria-hidden="true" viewbox="0 0 24 24" data-testid="ChevronRightIcon"><path d="M10 6 8.59 7.41 13.17 12l-4.58 4.59L10 18l6-6z"/></svg></div></div></div></li><li class="MuiTreeItem-root css-1oy5rnm" role="treeitem" aria-expanded="false" id="left-nav-treeview-0-5" tabindex="-1" style="margin-top:0.1875rem;margin-bottom:0.1875rem"><div class="css-khel7y MuiTreeItem-content" style="width:inherit"><div class="MuiTreeItem-iconContainer"/><div class="MuiTreeItem-label"><div class="css-znl8a3"><div class="MuiBox-root css-8atqhb"><div class="MuiTypography-root MuiTypography-body1 css-1hwyipb">数据迁移</div></div><svg class="MuiSvgIcon-root MuiSvgIcon-fontSizeMedium MuiTreeItem-ChevronRightIcon css-xjq79n" focusable="false" aria-hidden="true" viewbox="0 0 24 24" data-testid="ChevronRightIcon"><path d="M10 6 8.59 7.41 13.17 12l-4.58 4.59L10 18l6-6z"/></svg></div></div></div></li><li class="MuiTreeItem-root css-1oy5rnm" role="treeitem" aria-expanded="false" id="left-nav-treeview-0-6" tabindex="-1" style="margin-top:0.1875rem;margin-bottom:0.1875rem"><div class="css-khel7y MuiTreeItem-content" style="width:inherit"><div class="MuiTreeItem-iconContainer"/><div class="MuiTreeItem-label"><div class="css-znl8a3"><div class="MuiBox-root css-8atqhb"><div class="MuiTypography-root MuiTypography-body1 css-1hwyipb">数据集成</div></div><svg class="MuiSvgIcon-root MuiSvgIcon-fontSizeMedium MuiTreeItem-ChevronRightIcon css-xjq79n" focusable="false" aria-hidden="true" viewbox="0 0 24 24" data-testid="ChevronRightIcon"><path d="M10 6 8.59 7.41 13.17 12l-4.58 4.59L10 18l6-6z"/></svg></div></div></div></li><li class="MuiTreeItem-root css-1oy5rnm" role="treeitem" aria-expanded="false" id="left-nav-treeview-0-7" tabindex="-1" style="margin-top:0.1875rem;margin-bottom:0.1875rem"><div class="css-khel7y MuiTreeItem-content" style="width:inherit"><div class="MuiTreeItem-iconContainer"/><div class="MuiTreeItem-label"><div class="css-znl8a3"><div class="MuiBox-root css-8atqhb"><div class="MuiTypography-root MuiTypography-body1 css-1hwyipb">运维操作</div></div><svg class="MuiSvgIcon-root MuiSvgIcon-fontSizeMedium MuiTreeItem-ChevronRightIcon css-xjq79n" focusable="false" aria-hidden="true" viewbox="0 0 24 24" data-testid="ChevronRightIcon"><path d="M10 6 8.59 7.41 13.17 12l-4.58 4.59L10 18l6-6z"/></svg></div></div></div></li><li class="MuiTreeItem-root css-1oy5rnm" role="treeitem" aria-expanded="false" id="left-nav-treeview-0-8" tabindex="-1" style="margin-top:0.1875rem;margin-bottom:0.1875rem"><div class="css-khel7y MuiTreeItem-content" style="width:inherit"><div class="MuiTreeItem-iconContainer"/><div class="MuiTreeItem-label"><div class="css-znl8a3"><div class="MuiBox-root css-8atqhb"><div class="MuiTypography-root MuiTypography-body1 css-1hwyipb">监控与告警</div></div><svg class="MuiSvgIcon-root MuiSvgIcon-fontSizeMedium MuiTreeItem-ChevronRightIcon css-xjq79n" focusable="false" aria-hidden="true" viewbox="0 0 24 24" data-testid="ChevronRightIcon"><path d="M10 6 8.59 7.41 13.17 12l-4.58 4.59L10 18l6-6z"/></svg></div></div></div></li><li class="MuiTreeItem-root css-1oy5rnm" role="treeitem" aria-expanded="false" id="left-nav-treeview-0-9" tabindex="-1" style="margin-top:0.1875rem;margin-bottom:0.1875rem"><div class="css-khel7y MuiTreeItem-content" style="width:inherit"><div class="MuiTreeItem-iconContainer"/><div class="MuiTreeItem-label"><div class="css-znl8a3"><div class="MuiBox-root css-8atqhb"><div class="MuiTypography-root MuiTypography-body1 css-1hwyipb">故障诊断</div></div><svg class="MuiSvgIcon-root MuiSvgIcon-fontSizeMedium MuiTreeItem-ChevronRightIcon css-xjq79n" focusable="false" aria-hidden="true" viewbox="0 0 24 24" data-testid="ChevronRightIcon"><path d="M10 6 8.59 7.41 13.17 12l-4.58 4.59L10 18l6-6z"/></svg></div></div></div></li><li class="MuiTreeItem-root css-1oy5rnm" role="treeitem" aria-expanded="false" id="left-nav-treeview-0-10" tabindex="-1" style="margin-top:0.1875rem;margin-bottom:0.1875rem"><div class="css-khel7y MuiTreeItem-content" style="width:inherit"><div class="MuiTreeItem-iconContainer"/><div class="MuiTreeItem-label"><div class="css-znl8a3"><div class="MuiBox-root css-8atqhb"><div class="MuiTypography-root MuiTypography-body1 css-1hwyipb">性能调优</div></div><svg class="MuiSvgIcon-root MuiSvgIcon-fontSizeMedium MuiTreeItem-ChevronRightIcon css-xjq79n" focusable="false" aria-hidden="true" viewbox="0 0 24 24" data-testid="ChevronRightIcon"><path d="M10 6 8.59 7.41 13.17 12l-4.58 4.59L10 18l6-6z"/></svg></div></div></div></li><li class="MuiTreeItem-root css-1oy5rnm" role="treeitem" aria-expanded="false" id="left-nav-treeview-0-11" tabindex="-1" style="margin-top:0.1875rem;margin-bottom:0.1875rem"><div class="css-khel7y MuiTreeItem-content" style="width:inherit"><div class="MuiTreeItem-iconContainer"/><div class="MuiTreeItem-label"><div class="css-znl8a3"><div class="MuiBox-root css-8atqhb"><div class="MuiTypography-root MuiTypography-body1 css-1hwyipb">教程</div></div><svg class="MuiSvgIcon-root MuiSvgIcon-fontSizeMedium MuiTreeItem-ChevronRightIcon css-xjq79n" focusable="false" aria-hidden="true" viewbox="0 0 24 24" data-testid="ChevronRightIcon"><path d="M10 6 8.59 7.41 13.17 12l-4.58 4.59L10 18l6-6z"/></svg></div></div></div></li><li class="MuiTreeItem-root css-1oy5rnm" role="treeitem" aria-expanded="false" id="left-nav-treeview-0-12" tabindex="-1" style="margin-top:0.1875rem;margin-bottom:0.1875rem"><div class="css-khel7y MuiTreeItem-content" style="width:inherit"><div class="MuiTreeItem-iconContainer"/><div class="MuiTreeItem-label"><div class="css-znl8a3"><div class="MuiBox-root css-8atqhb"><div class="MuiTypography-root MuiTypography-body1 css-1hwyipb">TiDB 工具</div></div><svg class="MuiSvgIcon-root MuiSvgIcon-fontSizeMedium MuiTreeItem-ChevronRightIcon css-xjq79n" focusable="false" aria-hidden="true" viewbox="0 0 24 24" data-testid="ChevronRightIcon"><path d="M10 6 8.59 7.41 13.17 12l-4.58 4.59L10 18l6-6z"/></svg></div></div></div></li><li class="MuiTreeItem-root css-1oy5rnm" role="treeitem" aria-expanded="true" id="left-nav-treeview-0-13" tabindex="-1" style="margin-top:0.1875rem;margin-bottom:0.1875rem"><div class="css-khel7y MuiTreeItem-content Mui-expanded" style="width:inherit"><div class="MuiTreeItem-iconContainer"/><div class="MuiTreeItem-label"><div class="css-znl8a3"><div class="MuiBox-root css-8atqhb"><div class="MuiTypography-root MuiTypography-body1 css-1hwyipb">参考指南</div></div><style data-emotion="css 171pefp">.css-171pefp{-webkit-user-select:none;-moz-user-select:none;-ms-user-select:none;user-select:none;width:1em;height:1em;display:inline-block;fill:currentColor;-webkit-flex-shrink:0;-ms-flex-negative:0;flex-shrink:0;-webkit-transition:fill 200ms cubic-bezier(0.4, 0, 0.2, 1) 0ms;transition:fill 200ms cubic-bezier(0.4, 0, 0.2, 1) 0ms;font-size:1.5rem;fill:#999999;height:1rem;width:1rem;margin-left:auto;-webkit-transform:rotate(90deg);-moz-transform:rotate(90deg);-ms-transform:rotate(90deg);transform:rotate(90deg);}</style><svg class="MuiSvgIcon-root MuiSvgIcon-fontSizeMedium MuiTreeItem-ChevronRightIcon css-171pefp" focusable="false" aria-hidden="true" viewbox="0 0 24 24" data-testid="ChevronRightIcon"><path d="M10 6 8.59 7.41 13.17 12l-4.58 4.59L10 18l6-6z"/></svg></div></div></div><style data-emotion="css 1xxsnna">.css-1xxsnna{height:auto;overflow:visible;-webkit-transition:height 300ms cubic-bezier(0.4, 0, 0.2, 1) 0ms;transition:height 300ms cubic-bezier(0.4, 0, 0.2, 1) 0ms;margin:0;padding:0;margin-left:17px;}</style><ul class="MuiCollapse-root MuiCollapse-vertical MuiTreeItem-group MuiCollapse-entered css-1xxsnna" style="min-height:0px" role="group"><div class="MuiCollapse-wrapper MuiCollapse-vertical css-hboir5"><div class="MuiCollapse-wrapperInner MuiCollapse-vertical css-8atqhb"><li class="MuiTreeItem-root css-1oy5rnm" role="treeitem" aria-expanded="false" id="left-nav-treeview-0-13-0" tabindex="-1" style="margin-top:0.1875rem;margin-bottom:0.1875rem"><div class="css-khel7y MuiTreeItem-content" style="width:inherit"><div class="MuiTreeItem-iconContainer"/><div class="MuiTreeItem-label"><style data-emotion="css kb2j4b">.css-kb2j4b{display:-webkit-box;display:-webkit-flex;display:-ms-flexbox;display:flex;-webkit-flex-direction:row;-ms-flex-direction:row;flex-direction:row;min-height:1.75rem;-webkit-align-items:center;-webkit-box-align:center;-ms-flex-align:center;align-items:center;padding-left:0.5rem;padding-top:0.25rem;padding-bottom:0.25rem;}</style><div class="css-kb2j4b"><div class="MuiBox-root css-8atqhb"><div class="MuiTypography-root MuiTypography-body1 css-1hwyipb">架构</div></div><svg class="MuiSvgIcon-root MuiSvgIcon-fontSizeMedium MuiTreeItem-ChevronRightIcon css-xjq79n" focusable="false" aria-hidden="true" viewbox="0 0 24 24" data-testid="ChevronRightIcon"><path d="M10 6 8.59 7.41 13.17 12l-4.58 4.59L10 18l6-6z"/></svg></div></div></div></li><li class="MuiTreeItem-root css-1oy5rnm" role="treeitem" aria-expanded="false" id="left-nav-treeview-0-13-1" tabindex="-1" style="margin-top:0.1875rem;margin-bottom:0.1875rem"><div class="css-khel7y MuiTreeItem-content" style="width:inherit"><div class="MuiTreeItem-iconContainer"/><div class="MuiTreeItem-label"><div class="css-kb2j4b"><div class="MuiBox-root css-8atqhb"><div class="MuiTypography-root MuiTypography-body1 css-1hwyipb">存储引擎 TiKV</div></div><svg class="MuiSvgIcon-root MuiSvgIcon-fontSizeMedium MuiTreeItem-ChevronRightIcon css-xjq79n" focusable="false" aria-hidden="true" viewbox="0 0 24 24" data-testid="ChevronRightIcon"><path d="M10 6 8.59 7.41 13.17 12l-4.58 4.59L10 18l6-6z"/></svg></div></div></div></li><li class="MuiTreeItem-root css-1oy5rnm" role="treeitem" aria-expanded="false" id="left-nav-treeview-0-13-2" tabindex="-1" style="margin-top:0.1875rem;margin-bottom:0.1875rem"><div class="css-khel7y MuiTreeItem-content" style="width:inherit"><div class="MuiTreeItem-iconContainer"/><div class="MuiTreeItem-label"><div class="css-kb2j4b"><div class="MuiBox-root css-8atqhb"><div class="MuiTypography-root MuiTypography-body1 css-1hwyipb">存储引擎 TiFlash</div></div><svg class="MuiSvgIcon-root 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css-1oy5rnm" role="treeitem" id="left-nav-treeview-0-13-4" tabindex="-1" style="margin-top:0.1875rem;margin-bottom:0.1875rem"><div class="css-khel7y MuiTreeItem-content" style="width:inherit"><div class="MuiTreeItem-iconContainer"/><div class="MuiTreeItem-label"><div class="css-kb2j4b"><a style="text-decoration:none;width:100%;color:inherit" href="/zh/tidb/stable/system-variables"><div class="MuiBox-root css-8atqhb"><div class="MuiTypography-root MuiTypography-body1 css-1hwyipb">系统变量</div></div></a></div></div></div></li><li class="MuiTreeItem-root css-1oy5rnm" role="treeitem" aria-expanded="false" id="left-nav-treeview-0-13-5" tabindex="-1" style="margin-top:0.1875rem;margin-bottom:0.1875rem"><div class="css-khel7y MuiTreeItem-content" style="width:inherit"><div class="MuiTreeItem-iconContainer"/><div class="MuiTreeItem-label"><div class="css-kb2j4b"><div class="MuiBox-root css-8atqhb"><div class="MuiTypography-root MuiTypography-body1 css-1hwyipb">配置文件参数</div></div><svg 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class="MuiTreeItem-iconContainer"/><div class="MuiTreeItem-label"><div class="css-kb2j4b"><div class="MuiBox-root css-8atqhb"><div class="MuiTypography-root MuiTypography-body1 css-1hwyipb">监控指标</div></div><svg class="MuiSvgIcon-root MuiSvgIcon-fontSizeMedium MuiTreeItem-ChevronRightIcon css-xjq79n" focusable="false" aria-hidden="true" viewbox="0 0 24 24" data-testid="ChevronRightIcon"><path d="M10 6 8.59 7.41 13.17 12l-4.58 4.59L10 18l6-6z"/></svg></div></div></div></li><li class="MuiTreeItem-root css-1oy5rnm" role="treeitem" aria-expanded="false" id="left-nav-treeview-0-13-9" tabindex="-1" style="margin-top:0.1875rem;margin-bottom:0.1875rem"><div class="css-khel7y MuiTreeItem-content" style="width:inherit"><div class="MuiTreeItem-iconContainer"/><div class="MuiTreeItem-label"><div class="css-kb2j4b"><div class="MuiBox-root css-8atqhb"><div class="MuiTypography-root MuiTypography-body1 css-1hwyipb">安全加固</div></div><svg class="MuiSvgIcon-root MuiSvgIcon-fontSizeMedium 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13.17 12l-4.58 4.59L10 18l6-6z"/></svg></div></div></div></li><li class="MuiTreeItem-root css-1oy5rnm" role="treeitem" aria-expanded="false" id="left-nav-treeview-0-13-11-1" tabindex="-1" style="margin-top:0.1875rem;margin-bottom:0.1875rem"><div class="css-khel7y MuiTreeItem-content" style="width:inherit"><div class="MuiTreeItem-iconContainer"/><div class="MuiTreeItem-label"><div class="css-snygwd"><div class="MuiBox-root css-8atqhb"><div class="MuiTypography-root MuiTypography-body1 css-1hwyipb">SQL 语句</div></div><svg class="MuiSvgIcon-root MuiSvgIcon-fontSizeMedium MuiTreeItem-ChevronRightIcon css-xjq79n" focusable="false" aria-hidden="true" viewbox="0 0 24 24" data-testid="ChevronRightIcon"><path d="M10 6 8.59 7.41 13.17 12l-4.58 4.59L10 18l6-6z"/></svg></div></div></div></li><li class="MuiTreeItem-root css-1oy5rnm" role="treeitem" aria-expanded="false" id="left-nav-treeview-0-13-11-2" tabindex="-1" style="margin-top:0.1875rem;margin-bottom:0.1875rem"><div class="css-khel7y 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style="width:inherit"><div class="MuiTreeItem-iconContainer"/><div class="MuiTreeItem-label"><div class="css-snygwd"><a style="text-decoration:none;width:100%;color:inherit" href="/zh/tidb/stable/views"><div class="MuiBox-root css-8atqhb"><div class="MuiTypography-root MuiTypography-body1 css-1hwyipb">视图</div></div></a></div></div></div></li><li class="MuiTreeItem-root css-1oy5rnm" role="treeitem" id="left-nav-treeview-0-13-11-11" tabindex="-1" style="margin-top:0.1875rem;margin-bottom:0.1875rem"><div class="css-khel7y MuiTreeItem-content Mui-expanded" style="width:inherit"><div class="MuiTreeItem-iconContainer"/><div class="MuiTreeItem-label"><div class="css-snygwd"><a aria-current="page" style="text-decoration:none;width:100%;color:inherit" class="" href="/zh/tidb/stable/partitioned-table"><div class="MuiBox-root css-8atqhb"><div class="MuiTypography-root MuiTypography-body1 css-1hwyipb">分区表</div></div></a></div></div></div></li><li class="MuiTreeItem-root css-1oy5rnm" 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MuiTypography-body1 css-1hwyipb">缓存表</div></div></a></div></div></div></li><li class="MuiTreeItem-root css-1oy5rnm" role="treeitem" id="left-nav-treeview-0-13-11-14" tabindex="-1" style="margin-top:0.1875rem;margin-bottom:0.1875rem"><div class="css-khel7y MuiTreeItem-content" style="width:inherit"><div class="MuiTreeItem-iconContainer"/><div class="MuiTreeItem-label"><div class="css-snygwd"><a style="text-decoration:none;width:100%;color:inherit" href="/zh/tidb/stable/foreign-key"><div class="MuiBox-root css-8atqhb"><div class="MuiTypography-root MuiTypography-body1 css-1hwyipb">外键约束</div></div></a></div></div></div></li><li class="MuiTreeItem-root css-1oy5rnm" role="treeitem" aria-expanded="false" id="left-nav-treeview-0-13-11-15" tabindex="-1" style="margin-top:0.1875rem;margin-bottom:0.1875rem"><div class="css-khel7y MuiTreeItem-content" style="width:inherit"><div class="MuiTreeItem-iconContainer"/><div class="MuiTreeItem-label"><div class="css-snygwd"><div class="MuiBox-root css-8atqhb"><div class="MuiTypography-root MuiTypography-body1 css-1hwyipb">字符集和排序</div></div><svg class="MuiSvgIcon-root MuiSvgIcon-fontSizeMedium MuiTreeItem-ChevronRightIcon css-xjq79n" focusable="false" aria-hidden="true" viewbox="0 0 24 24" data-testid="ChevronRightIcon"><path d="M10 6 8.59 7.41 13.17 12l-4.58 4.59L10 18l6-6z"/></svg></div></div></div></li><li class="MuiTreeItem-root css-1oy5rnm" role="treeitem" id="left-nav-treeview-0-13-11-16" tabindex="-1" style="margin-top:0.1875rem;margin-bottom:0.1875rem"><div class="css-khel7y MuiTreeItem-content" style="width:inherit"><div class="MuiTreeItem-iconContainer"/><div class="MuiTreeItem-label"><div class="css-snygwd"><a style="text-decoration:none;width:100%;color:inherit" href="/zh/tidb/stable/placement-rules-in-sql"><div class="MuiBox-root css-8atqhb"><div class="MuiTypography-root MuiTypography-body1 css-1hwyipb">Placement Rules in SQL</div></div></a></div></div></div></li><li class="MuiTreeItem-root css-1oy5rnm" 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(min-width:0px){.css-90fn5w{-webkit-flex-direction:column-reverse;-ms-flex-direction:column-reverse;flex-direction:column-reverse;}}@media (min-width:600px){.css-90fn5w{-webkit-flex-direction:row;-ms-flex-direction:row;flex-direction:row;}}</style><div class="css-90fn5w"><style data-emotion="css vofosd">.css-vofosd{padding:1.5rem 0;}@media (min-width:0px){.css-vofosd{width:100%;}}@media (min-width:600px){.css-vofosd{width:calc(100% - 17.5rem);}}</style><div class="MuiBox-root css-vofosd"><style data-emotion="css 1ekb41w">.css-1ekb41w{width:100%;margin-left:auto;box-sizing:border-box;margin-right:auto;display:block;padding-left:16px;padding-right:16px;}@media (min-width:600px){.css-1ekb41w{padding-left:24px;padding-right:24px;}}@media (min-width:1536px){.css-1ekb41w{max-width:1536px;}}</style><div class="MuiContainer-root MuiContainer-maxWidthXl doc-content css-1ekb41w"><div class="markdown-body MuiBox-root css-0"><h1 id="分区表" style="position:relative"><a href="#%E5%88%86%E5%8C%BA%E8%A1%A8" aria-label="分区表 permalink" class="anchor before"><svg aria-hidden="true" focusable="false" height="16" version="1.1" viewbox="0 0 16 16" width="16"><path fill-rule="evenodd" d="M4 9h1v1H4c-1.5 0-3-1.69-3-3.5S2.55 3 4 3h4c1.45 0 3 1.69 3 3.5 0 1.41-.91 2.72-2 3.25V8.59c.58-.45 1-1.27 1-2.09C10 5.22 8.98 4 8 4H4c-.98 0-2 1.22-2 2.5S3 9 4 9zm9-3h-1v1h1c1 0 2 1.22 2 2.5S13.98 12 13 12H9c-.98 0-2-1.22-2-2.5 0-.83.42-1.64 1-2.09V6.25c-1.09.53-2 1.84-2 3.25C6 11.31 7.55 13 9 13h4c1.45 0 3-1.69 3-3.5S14.5 6 13 6z"/></svg></a>分区表</h1><p>本文介绍 TiDB 的分区表。</p><h2 id="分区类型" style="position:relative"><a href="#%E5%88%86%E5%8C%BA%E7%B1%BB%E5%9E%8B" aria-label="分区类型 permalink" class="anchor before"><svg aria-hidden="true" focusable="false" height="16" version="1.1" viewbox="0 0 16 16" width="16"><path fill-rule="evenodd" d="M4 9h1v1H4c-1.5 0-3-1.69-3-3.5S2.55 3 4 3h4c1.45 0 3 1.69 3 3.5 0 1.41-.91 2.72-2 3.25V8.59c.58-.45 1-1.27 1-2.09C10 5.22 8.98 4 8 4H4c-.98 0-2 1.22-2 2.5S3 9 4 9zm9-3h-1v1h1c1 0 2 1.22 2 2.5S13.98 12 13 12H9c-.98 0-2-1.22-2-2.5 0-.83.42-1.64 1-2.09V6.25c-1.09.53-2 1.84-2 3.25C6 11.31 7.55 13 9 13h4c1.45 0 3-1.69 3-3.5S14.5 6 13 6z"/></svg></a>分区类型</h2><p>本节介绍 TiDB 中的分区类型。当前支持的类型包括 <a href="#range-%E5%88%86%E5%8C%BA">Range 分区</a>、<a href="#range-columns-%E5%88%86%E5%8C%BA">Range COLUMNS 分区</a>、<a href="#range-interval-%E5%88%86%E5%8C%BA">Range INTERVAL 分区</a>、<a href="#list-%E5%88%86%E5%8C%BA">List 分区</a>、<a href="#list-columns-%E5%88%86%E5%8C%BA">List COLUMNS 分区</a>、<a href="#hash-%E5%88%86%E5%8C%BA">Hash 分区</a>和 <a href="#key-%E5%88%86%E5%8C%BA">Key 分区</a>。</p><ul><li>Range 分区、Range COLUMNS 分区、List 分区和 List COLUMNS 分区可以用于解决业务中大量删除带来的性能问题，支持快速删除分区。</li><li>Hash 分区和 Key 分区可以用于大量写入场景下的数据打散。与 Hash 分区相比，Key 分区支持多列打散和非整数类型字段的打散。</li></ul><h3 id="range-分区" style="position:relative"><a href="#range-%E5%88%86%E5%8C%BA" aria-label="range 分区 permalink" class="anchor before"><svg aria-hidden="true" focusable="false" height="16" version="1.1" viewbox="0 0 16 16" width="16"><path fill-rule="evenodd" d="M4 9h1v1H4c-1.5 0-3-1.69-3-3.5S2.55 3 4 3h4c1.45 0 3 1.69 3 3.5 0 1.41-.91 2.72-2 3.25V8.59c.58-.45 1-1.27 1-2.09C10 5.22 8.98 4 8 4H4c-.98 0-2 1.22-2 2.5S3 9 4 9zm9-3h-1v1h1c1 0 2 1.22 2 2.5S13.98 12 13 12H9c-.98 0-2-1.22-2-2.5 0-.83.42-1.64 1-2.09V6.25c-1.09.53-2 1.84-2 3.25C6 11.31 7.55 13 9 13h4c1.45 0 3-1.69 3-3.5S14.5 6 13 6z"/></svg></a>Range 分区</h3><p>一个表按 Range 分区是指，对于表的每个分区中包含的所有行，按分区表达式计算的值都落在给定的范围内。Range 必须是连续的，并且不能有重叠，通过使用 <code>VALUES LESS THAN</code> 进行定义。</p><p>下列场景中，假设你要创建一个人事记录的表：</p><pre><code class="hljs language-sql"><style data-emotion="css 1qhimia">.css-1qhimia{margin-right:3rem;overflow:auto;}</style><div class="MuiBox-root css-1qhimia"><span class="hljs-keyword">CREATE</span> <span class="hljs-keyword">TABLE</span> employees ( id <span class="hljs-type">INT</span> <span class="hljs-keyword">NOT</span> <span class="hljs-keyword">NULL</span>, fname <span class="hljs-type">VARCHAR</span>(<span class="hljs-number">30</span>), lname <span class="hljs-type">VARCHAR</span>(<span class="hljs-number">30</span>), hired <span class="hljs-type">DATE</span> <span class="hljs-keyword">NOT</span> <span class="hljs-keyword">NULL</span> <span class="hljs-keyword">DEFAULT</span> <span class="hljs-string">'1970-01-01'</span>, separated <span class="hljs-type">DATE</span> <span class="hljs-keyword">DEFAULT</span> <span class="hljs-string">'9999-12-31'</span>, job_code <span class="hljs-type">INT</span>, store_id <span class="hljs-type">INT</span> <span class="hljs-keyword">NOT</span> <span class="hljs-keyword">NULL</span> </div><style data-emotion="css ux9q70">.css-ux9q70{text-align:center;-webkit-flex:0 0 auto;-ms-flex:0 0 auto;flex:0 0 auto;font-size:1.5rem;padding:8px;border-radius:50%;overflow:visible;color:rgba(0, 0, 0, 0.54);-webkit-transition:background-color 150ms cubic-bezier(0.4, 0, 0.2, 1) 0ms;transition:background-color 150ms cubic-bezier(0.4, 0, 0.2, 1) 0ms;padding:5px;font-size:1.125rem;top:0.625rem;right:2.4rem;background:transparent;border:unset;}.css-ux9q70:hover{background-color:rgba(0, 0, 0, 0.04);}@media (hover: none){.css-ux9q70:hover{background-color:transparent;}}.css-ux9q70.Mui-disabled{background-color:transparent;color:rgba(0, 0, 0, 0.26);}</style><style data-emotion="css 1rmx1rm">.css-1rmx1rm{display:-webkit-inline-box;display:-webkit-inline-flex;display:-ms-inline-flexbox;display:inline-flex;-webkit-align-items:center;-webkit-box-align:center;-ms-flex-align:center;align-items:center;-webkit-box-pack:center;-ms-flex-pack:center;-webkit-justify-content:center;justify-content:center;position:relative;box-sizing:border-box;-webkit-tap-highlight-color:transparent;background-color:transparent;outline:0;border:0;margin:0;border-radius:0;padding:0;cursor:pointer;-webkit-user-select:none;-moz-user-select:none;-ms-user-select:none;user-select:none;vertical-align:middle;-moz-appearance:none;-webkit-appearance:none;-webkit-text-decoration:none;text-decoration:none;color:inherit;text-align:center;-webkit-flex:0 0 auto;-ms-flex:0 0 auto;flex:0 0 auto;font-size:1.5rem;padding:8px;border-radius:50%;overflow:visible;color:rgba(0, 0, 0, 0.54);-webkit-transition:background-color 150ms cubic-bezier(0.4, 0, 0.2, 1) 0ms;transition:background-color 150ms cubic-bezier(0.4, 0, 0.2, 1) 0ms;padding:5px;font-size:1.125rem;top:0.625rem;right:2.4rem;background:transparent;border:unset;}.css-1rmx1rm::-moz-focus-inner{border-style:none;}.css-1rmx1rm.Mui-disabled{pointer-events:none;cursor:default;}@media print{.css-1rmx1rm{-webkit-print-color-adjust:exact;color-adjust:exact;}}.css-1rmx1rm:hover{background-color:rgba(0, 0, 0, 0.04);}@media (hover: none){.css-1rmx1rm:hover{background-color:transparent;}}.css-1rmx1rm.Mui-disabled{background-color:transparent;color:rgba(0, 0, 0, 0.26);}</style><button class="MuiButtonBase-root MuiIconButton-root MuiIconButton-sizeSmall css-1rmx1rm" tabindex="0" type="button" aria-label="Toggle code wrap"><style data-emotion="css 1cw4hi4">.css-1cw4hi4{-webkit-user-select:none;-moz-user-select:none;-ms-user-select:none;user-select:none;width:1em;height:1em;display:inline-block;fill:currentColor;-webkit-flex-shrink:0;-ms-flex-negative:0;flex-shrink:0;-webkit-transition:fill 200ms cubic-bezier(0.4, 0, 0.2, 1) 0ms;transition:fill 200ms cubic-bezier(0.4, 0, 0.2, 1) 0ms;font-size:inherit;}</style><svg class="MuiSvgIcon-root MuiSvgIcon-fontSizeInherit css-1cw4hi4" focusable="false" aria-hidden="true" viewbox="0 0 24 24" data-testid="WrapTextIcon"><path d="M4 19h6v-2H4v2zM20 5H4v2h16V5zm-3 6H4v2h13.25c1.1 0 2 .9 2 2s-.9 2-2 2H15v-2l-3 3 3 3v-2h2c2.21 0 4-1.79 4-4s-1.79-4-4-4z"/></svg></button><style data-emotion="css 1e2dcm1">.css-1e2dcm1{z-index:1500;pointer-events:none;}</style><style data-emotion="css okvapm">.css-okvapm{z-index:1500;pointer-events:none;}</style><style data-emotion="css rnn29l">.css-rnn29l{text-align:center;-webkit-flex:0 0 auto;-ms-flex:0 0 auto;flex:0 0 auto;font-size:1.5rem;padding:8px;border-radius:50%;overflow:visible;color:rgba(0, 0, 0, 0.54);-webkit-transition:background-color 150ms cubic-bezier(0.4, 0, 0.2, 1) 0ms;transition:background-color 150ms cubic-bezier(0.4, 0, 0.2, 1) 0ms;padding:5px;font-size:1.125rem;top:0.625rem;right:0.625rem;background:transparent;border:unset;}.css-rnn29l:hover{background-color:rgba(0, 0, 0, 0.04);}@media (hover: none){.css-rnn29l:hover{background-color:transparent;}}.css-rnn29l.Mui-disabled{background-color:transparent;color:rgba(0, 0, 0, 0.26);}</style><style data-emotion="css fxo539">.css-fxo539{display:-webkit-inline-box;display:-webkit-inline-flex;display:-ms-inline-flexbox;display:inline-flex;-webkit-align-items:center;-webkit-box-align:center;-ms-flex-align:center;align-items:center;-webkit-box-pack:center;-ms-flex-pack:center;-webkit-justify-content:center;justify-content:center;position:relative;box-sizing:border-box;-webkit-tap-highlight-color:transparent;background-color:transparent;outline:0;border:0;margin:0;border-radius:0;padding:0;cursor:pointer;-webkit-user-select:none;-moz-user-select:none;-ms-user-select:none;user-select:none;vertical-align:middle;-moz-appearance:none;-webkit-appearance:none;-webkit-text-decoration:none;text-decoration:none;color:inherit;text-align:center;-webkit-flex:0 0 auto;-ms-flex:0 0 auto;flex:0 0 auto;font-size:1.5rem;padding:8px;border-radius:50%;overflow:visible;color:rgba(0, 0, 0, 0.54);-webkit-transition:background-color 150ms cubic-bezier(0.4, 0, 0.2, 1) 0ms;transition:background-color 150ms cubic-bezier(0.4, 0, 0.2, 1) 0ms;padding:5px;font-size:1.125rem;top:0.625rem;right:0.625rem;background:transparent;border:unset;}.css-fxo539::-moz-focus-inner{border-style:none;}.css-fxo539.Mui-disabled{pointer-events:none;cursor:default;}@media print{.css-fxo539{-webkit-print-color-adjust:exact;color-adjust:exact;}}.css-fxo539:hover{background-color:rgba(0, 0, 0, 0.04);}@media (hover: none){.css-fxo539:hover{background-color:transparent;}}.css-fxo539.Mui-disabled{background-color:transparent;color:rgba(0, 0, 0, 0.26);}</style><button class="MuiButtonBase-root MuiIconButton-root MuiIconButton-sizeSmall css-fxo539" tabindex="0" type="button" aria-label="copy"><svg class="MuiSvgIcon-root MuiSvgIcon-fontSizeInherit css-1cw4hi4" focusable="false" aria-hidden="true" viewbox="0 0 24 24" data-testid="ContentCopyIcon"><path d="M16 1H4c-1.1 0-2 .9-2 2v14h2V3h12V1zm3 4H8c-1.1 0-2 .9-2 2v14c0 1.1.9 2 2 2h11c1.1 0 2-.9 2-2V7c0-1.1-.9-2-2-2zm0 16H8V7h11v14z"/></svg></button></code></pre><p>你可以根据需求按各种方式进行 Range 分区。其中一种方式是按 <code>store_id</code> 列进行分区：</p><pre><code class="hljs language-sql"><div class="MuiBox-root css-1qhimia"><span class="hljs-keyword">CREATE</span> <span class="hljs-keyword">TABLE</span> employees ( id <span class="hljs-type">INT</span> <span class="hljs-keyword">NOT</span> <span class="hljs-keyword">NULL</span>, fname <span class="hljs-type">VARCHAR</span>(<span class="hljs-number">30</span>), lname <span class="hljs-type">VARCHAR</span>(<span class="hljs-number">30</span>), hired <span class="hljs-type">DATE</span> <span class="hljs-keyword">NOT</span> <span class="hljs-keyword">NULL</span> <span class="hljs-keyword">DEFAULT</span> <span class="hljs-string">'1970-01-01'</span>, separated <span class="hljs-type">DATE</span> <span class="hljs-keyword">DEFAULT</span> <span class="hljs-string">'9999-12-31'</span>, job_code <span class="hljs-type">INT</span>, store_id <span class="hljs-type">INT</span> <span class="hljs-keyword">NOT</span> <span class="hljs-keyword">NULL</span> <span class="hljs-keyword">PARTITION</span> <span class="hljs-keyword">BY</span> <span class="hljs-keyword">RANGE</span> (store_id) ( <span class="hljs-keyword">PARTITION</span> p0 <span class="hljs-keyword">VALUES</span> LESS THAN (<span class="hljs-number">6</span>), <span class="hljs-keyword">PARTITION</span> p1 <span class="hljs-keyword">VALUES</span> LESS THAN (<span class="hljs-number">11</span>), <span class="hljs-keyword">PARTITION</span> p2 <span class="hljs-keyword">VALUES</span> LESS THAN (<span class="hljs-number">16</span>), <span class="hljs-keyword">PARTITION</span> p3 <span class="hljs-keyword">VALUES</span> LESS THAN (<span class="hljs-number">21</span>) </div><button class="MuiButtonBase-root MuiIconButton-root MuiIconButton-sizeSmall css-1rmx1rm" tabindex="0" type="button" aria-label="Toggle code wrap"><svg class="MuiSvgIcon-root MuiSvgIcon-fontSizeInherit css-1cw4hi4" focusable="false" aria-hidden="true" viewbox="0 0 24 24" data-testid="WrapTextIcon"><path d="M4 19h6v-2H4v2zM20 5H4v2h16V5zm-3 6H4v2h13.25c1.1 0 2 .9 2 2s-.9 2-2 2H15v-2l-3 3 3 3v-2h2c2.21 0 4-1.79 4-4s-1.79-4-4-4z"/></svg></button><button class="MuiButtonBase-root MuiIconButton-root MuiIconButton-sizeSmall css-fxo539" tabindex="0" type="button" aria-label="copy"><svg class="MuiSvgIcon-root MuiSvgIcon-fontSizeInherit css-1cw4hi4" focusable="false" aria-hidden="true" viewbox="0 0 24 24" data-testid="ContentCopyIcon"><path d="M16 1H4c-1.1 0-2 .9-2 2v14h2V3h12V1zm3 4H8c-1.1 0-2 .9-2 2v14c0 1.1.9 2 2 2h11c1.1 0 2-.9 2-2V7c0-1.1-.9-2-2-2zm0 16H8V7h11v14z"/></svg></button></code></pre><p>在这个分区模式中，所有 <code>store_id</code> 为 1 到 5 的员工，都存储在分区 <code>p0</code> 里面，<code>store_id</code> 为 6 到 10 的员工则存储在分区 <code>p1</code> 里面。Range 分区要求，分区的定义必须是有序的，按从小到大递增。</p><p>新插入一行数据 <code>(72, 'Tom', 'John', '2015-06-25', NULL, NULL, 15)</code> 将会落到分区 <code>p2</code> 里面。但如果你插入一条 <code>store_id</code> 大于 20 的记录，则会报错，因为 TiDB 无法知晓应该将它插入到哪个分区。这种情况下，可以在建表时使用最大值：</p><pre><code class="hljs language-sql"><div class="MuiBox-root css-1qhimia"><span class="hljs-keyword">CREATE</span> <span class="hljs-keyword">TABLE</span> employees ( id <span class="hljs-type">INT</span> <span class="hljs-keyword">NOT</span> <span class="hljs-keyword">NULL</span>, fname <span class="hljs-type">VARCHAR</span>(<span class="hljs-number">30</span>), lname <span class="hljs-type">VARCHAR</span>(<span class="hljs-number">30</span>), hired <span class="hljs-type">DATE</span> <span class="hljs-keyword">NOT</span> <span class="hljs-keyword">NULL</span> <span class="hljs-keyword">DEFAULT</span> <span class="hljs-string">'1970-01-01'</span>, separated <span class="hljs-type">DATE</span> <span class="hljs-keyword">DEFAULT</span> <span class="hljs-string">'9999-12-31'</span>, job_code <span class="hljs-type">INT</span>, store_id <span class="hljs-type">INT</span> <span class="hljs-keyword">NOT</span> <span class="hljs-keyword">NULL</span> <span class="hljs-keyword">PARTITION</span> <span class="hljs-keyword">BY</span> <span class="hljs-keyword">RANGE</span> (store_id) ( <span class="hljs-keyword">PARTITION</span> p0 <span class="hljs-keyword">VALUES</span> LESS THAN (<span class="hljs-number">6</span>), <span class="hljs-keyword">PARTITION</span> p1 <span class="hljs-keyword">VALUES</span> LESS THAN (<span class="hljs-number">11</span>), <span class="hljs-keyword">PARTITION</span> p2 <span class="hljs-keyword">VALUES</span> LESS THAN (<span class="hljs-number">16</span>), <span class="hljs-keyword">PARTITION</span> p3 <span class="hljs-keyword">VALUES</span> LESS THAN MAXVALUE </div><button class="MuiButtonBase-root MuiIconButton-root MuiIconButton-sizeSmall css-1rmx1rm" tabindex="0" type="button" aria-label="Toggle code wrap"><svg class="MuiSvgIcon-root MuiSvgIcon-fontSizeInherit css-1cw4hi4" focusable="false" aria-hidden="true" viewbox="0 0 24 24" data-testid="WrapTextIcon"><path d="M4 19h6v-2H4v2zM20 5H4v2h16V5zm-3 6H4v2h13.25c1.1 0 2 .9 2 2s-.9 2-2 2H15v-2l-3 3 3 3v-2h2c2.21 0 4-1.79 4-4s-1.79-4-4-4z"/></svg></button><button class="MuiButtonBase-root MuiIconButton-root MuiIconButton-sizeSmall css-fxo539" tabindex="0" type="button" aria-label="copy"><svg class="MuiSvgIcon-root MuiSvgIcon-fontSizeInherit css-1cw4hi4" focusable="false" aria-hidden="true" viewbox="0 0 24 24" data-testid="ContentCopyIcon"><path d="M16 1H4c-1.1 0-2 .9-2 2v14h2V3h12V1zm3 4H8c-1.1 0-2 .9-2 2v14c0 1.1.9 2 2 2h11c1.1 0 2-.9 2-2V7c0-1.1-.9-2-2-2zm0 16H8V7h11v14z"/></svg></button></code></pre><p><code>MAXVALUE</code> 表示一个比所有整数都大的整数。现在，所有 <code>store_id</code> 列大于等于 16 的记录都会存储在 <code>p3</code> 分区中。</p><p>你也可以按员工的职位编号进行分区，也就是使用 <code>job_code</code> 列的值进行分区。假设两位数字编号是用于普通员工，三位数字编号是用于办公室以及客户支持，四位数字编号是管理层职位，那么你可以这样建表：</p><pre><code class="hljs language-sql"><div class="MuiBox-root css-1qhimia"><span class="hljs-keyword">CREATE</span> <span class="hljs-keyword">TABLE</span> employees ( id <span class="hljs-type">INT</span> <span class="hljs-keyword">NOT</span> <span class="hljs-keyword">NULL</span>, fname <span class="hljs-type">VARCHAR</span>(<span class="hljs-number">30</span>), lname <span class="hljs-type">VARCHAR</span>(<span class="hljs-number">30</span>), hired <span class="hljs-type">DATE</span> <span class="hljs-keyword">NOT</span> <span class="hljs-keyword">NULL</span> <span class="hljs-keyword">DEFAULT</span> <span class="hljs-string">'1970-01-01'</span>, separated <span class="hljs-type">DATE</span> <span class="hljs-keyword">DEFAULT</span> <span class="hljs-string">'9999-12-31'</span>, job_code <span class="hljs-type">INT</span>, store_id <span class="hljs-type">INT</span> <span class="hljs-keyword">NOT</span> <span class="hljs-keyword">NULL</span> <span class="hljs-keyword">PARTITION</span> <span class="hljs-keyword">BY</span> <span class="hljs-keyword">RANGE</span> (job_code) ( <span class="hljs-keyword">PARTITION</span> p0 <span class="hljs-keyword">VALUES</span> LESS THAN (<span class="hljs-number">100</span>), <span class="hljs-keyword">PARTITION</span> p1 <span class="hljs-keyword">VALUES</span> LESS THAN (<span class="hljs-number">1000</span>), <span class="hljs-keyword">PARTITION</span> p2 <span class="hljs-keyword">VALUES</span> LESS THAN (<span class="hljs-number">10000</span>) </div><button class="MuiButtonBase-root MuiIconButton-root MuiIconButton-sizeSmall css-1rmx1rm" tabindex="0" type="button" aria-label="Toggle code wrap"><svg class="MuiSvgIcon-root MuiSvgIcon-fontSizeInherit css-1cw4hi4" focusable="false" aria-hidden="true" viewbox="0 0 24 24" data-testid="WrapTextIcon"><path d="M4 19h6v-2H4v2zM20 5H4v2h16V5zm-3 6H4v2h13.25c1.1 0 2 .9 2 2s-.9 2-2 2H15v-2l-3 3 3 3v-2h2c2.21 0 4-1.79 4-4s-1.79-4-4-4z"/></svg></button><button class="MuiButtonBase-root MuiIconButton-root MuiIconButton-sizeSmall css-fxo539" tabindex="0" type="button" aria-label="copy"><svg class="MuiSvgIcon-root MuiSvgIcon-fontSizeInherit css-1cw4hi4" focusable="false" aria-hidden="true" viewbox="0 0 24 24" data-testid="ContentCopyIcon"><path d="M16 1H4c-1.1 0-2 .9-2 2v14h2V3h12V1zm3 4H8c-1.1 0-2 .9-2 2v14c0 1.1.9 2 2 2h11c1.1 0 2-.9 2-2V7c0-1.1-.9-2-2-2zm0 16H8V7h11v14z"/></svg></button></code></pre><p>在这个例子中，所有普通员工存储在 <code>p0</code> 分区，办公室以及支持人员在 <code>p1</code> 分区，管理者在 <code>p2</code> 分区。</p><p>除了可以按 <code>store_id</code> 切分，你还可以按日期切分。例如，假设按员工离职的年份进行分区：</p><pre><code class="hljs language-sql"><div class="MuiBox-root css-1qhimia"><span class="hljs-keyword">CREATE</span> <span class="hljs-keyword">TABLE</span> employees ( id <span class="hljs-type">INT</span> <span class="hljs-keyword">NOT</span> <span class="hljs-keyword">NULL</span>, fname <span class="hljs-type">VARCHAR</span>(<span class="hljs-number">30</span>), lname <span class="hljs-type">VARCHAR</span>(<span class="hljs-number">30</span>), hired <span class="hljs-type">DATE</span> <span class="hljs-keyword">NOT</span> <span class="hljs-keyword">NULL</span> <span class="hljs-keyword">DEFAULT</span> <span class="hljs-string">'1970-01-01'</span>, separated <span class="hljs-type">DATE</span> <span class="hljs-keyword">DEFAULT</span> <span class="hljs-string">'9999-12-31'</span>, job_code <span class="hljs-type">INT</span>, store_id <span class="hljs-type">INT</span> <span class="hljs-keyword">PARTITION</span> <span class="hljs-keyword">BY</span> <span class="hljs-keyword">RANGE</span> ( <span class="hljs-keyword">YEAR</span>(separated) ) ( <span class="hljs-keyword">PARTITION</span> p0 <span class="hljs-keyword">VALUES</span> LESS THAN (<span class="hljs-number">1991</span>), <span class="hljs-keyword">PARTITION</span> p1 <span class="hljs-keyword">VALUES</span> LESS THAN (<span class="hljs-number">1996</span>), <span class="hljs-keyword">PARTITION</span> p2 <span class="hljs-keyword">VALUES</span> LESS THAN (<span class="hljs-number">2001</span>), <span class="hljs-keyword">PARTITION</span> p3 <span class="hljs-keyword">VALUES</span> LESS THAN MAXVALUE </div><button class="MuiButtonBase-root MuiIconButton-root MuiIconButton-sizeSmall css-1rmx1rm" tabindex="0" type="button" aria-label="Toggle code wrap"><svg class="MuiSvgIcon-root MuiSvgIcon-fontSizeInherit css-1cw4hi4" focusable="false" aria-hidden="true" viewbox="0 0 24 24" data-testid="WrapTextIcon"><path d="M4 19h6v-2H4v2zM20 5H4v2h16V5zm-3 6H4v2h13.25c1.1 0 2 .9 2 2s-.9 2-2 2H15v-2l-3 3 3 3v-2h2c2.21 0 4-1.79 4-4s-1.79-4-4-4z"/></svg></button><button class="MuiButtonBase-root MuiIconButton-root MuiIconButton-sizeSmall css-fxo539" tabindex="0" type="button" aria-label="copy"><svg class="MuiSvgIcon-root MuiSvgIcon-fontSizeInherit css-1cw4hi4" focusable="false" aria-hidden="true" viewbox="0 0 24 24" data-testid="ContentCopyIcon"><path d="M16 1H4c-1.1 0-2 .9-2 2v14h2V3h12V1zm3 4H8c-1.1 0-2 .9-2 2v14c0 1.1.9 2 2 2h11c1.1 0 2-.9 2-2V7c0-1.1-.9-2-2-2zm0 16H8V7h11v14z"/></svg></button></code></pre><p>在 Range 分区中，可以基于 <code>timestamp</code> 列的值分区，并使用 <code>unix_timestamp()</code> 函数，例如：</p><pre><code class="hljs language-sql"><div class="MuiBox-root css-1qhimia"><span class="hljs-keyword">CREATE</span> <span class="hljs-keyword">TABLE</span> quarterly_report_status ( report_id <span class="hljs-type">INT</span> <span class="hljs-keyword">NOT</span> <span class="hljs-keyword">NULL</span>, report_status <span class="hljs-type">VARCHAR</span>(<span class="hljs-number">20</span>) <span class="hljs-keyword">NOT</span> <span class="hljs-keyword">NULL</span>, report_updated <span class="hljs-type">TIMESTAMP</span> <span class="hljs-keyword">NOT</span> <span class="hljs-keyword">NULL</span> <span class="hljs-keyword">DEFAULT</span> <span class="hljs-built_in">CURRENT_TIMESTAMP</span> <span class="hljs-keyword">ON</span> <span class="hljs-keyword">UPDATE</span> <span class="hljs-built_in">CURRENT_TIMESTAMP</span> <span class="hljs-keyword">PARTITION</span> <span class="hljs-keyword">BY</span> <span class="hljs-keyword">RANGE</span> ( UNIX_TIMESTAMP(report_updated) ) ( <span class="hljs-keyword">PARTITION</span> p0 <span class="hljs-keyword">VALUES</span> LESS THAN ( UNIX_TIMESTAMP(<span class="hljs-string">'2008-01-01 00:00:00'</span>) ), <span class="hljs-keyword">PARTITION</span> p1 <span class="hljs-keyword">VALUES</span> LESS THAN ( UNIX_TIMESTAMP(<span class="hljs-string">'2008-04-01 00:00:00'</span>) ), <span class="hljs-keyword">PARTITION</span> p2 <span class="hljs-keyword">VALUES</span> LESS THAN ( UNIX_TIMESTAMP(<span class="hljs-string">'2008-07-01 00:00:00'</span>) ), <span class="hljs-keyword">PARTITION</span> p3 <span class="hljs-keyword">VALUES</span> LESS THAN ( UNIX_TIMESTAMP(<span class="hljs-string">'2008-10-01 00:00:00'</span>) ), <span class="hljs-keyword">PARTITION</span> p4 <span class="hljs-keyword">VALUES</span> LESS THAN ( UNIX_TIMESTAMP(<span class="hljs-string">'2009-01-01 00:00:00'</span>) ), <span class="hljs-keyword">PARTITION</span> p5 <span class="hljs-keyword">VALUES</span> LESS THAN ( UNIX_TIMESTAMP(<span class="hljs-string">'2009-04-01 00:00:00'</span>) ), <span class="hljs-keyword">PARTITION</span> p6 <span class="hljs-keyword">VALUES</span> LESS THAN ( UNIX_TIMESTAMP(<span class="hljs-string">'2009-07-01 00:00:00'</span>) ), <span class="hljs-keyword">PARTITION</span> p7 <span class="hljs-keyword">VALUES</span> LESS THAN ( UNIX_TIMESTAMP(<span class="hljs-string">'2009-10-01 00:00:00'</span>) ), <span class="hljs-keyword">PARTITION</span> p8 <span class="hljs-keyword">VALUES</span> LESS THAN ( UNIX_TIMESTAMP(<span class="hljs-string">'2010-01-01 00:00:00'</span>) ), <span class="hljs-keyword">PARTITION</span> p9 <span class="hljs-keyword">VALUES</span> LESS THAN (MAXVALUE) </div><button class="MuiButtonBase-root MuiIconButton-root MuiIconButton-sizeSmall css-1rmx1rm" tabindex="0" type="button" aria-label="Toggle code wrap"><svg class="MuiSvgIcon-root MuiSvgIcon-fontSizeInherit css-1cw4hi4" focusable="false" aria-hidden="true" viewbox="0 0 24 24" data-testid="WrapTextIcon"><path d="M4 19h6v-2H4v2zM20 5H4v2h16V5zm-3 6H4v2h13.25c1.1 0 2 .9 2 2s-.9 2-2 2H15v-2l-3 3 3 3v-2h2c2.21 0 4-1.79 4-4s-1.79-4-4-4z"/></svg></button><button class="MuiButtonBase-root MuiIconButton-root MuiIconButton-sizeSmall css-fxo539" tabindex="0" type="button" aria-label="copy"><svg class="MuiSvgIcon-root MuiSvgIcon-fontSizeInherit css-1cw4hi4" focusable="false" aria-hidden="true" viewbox="0 0 24 24" data-testid="ContentCopyIcon"><path d="M16 1H4c-1.1 0-2 .9-2 2v14h2V3h12V1zm3 4H8c-1.1 0-2 .9-2 2v14c0 1.1.9 2 2 2h11c1.1 0 2-.9 2-2V7c0-1.1-.9-2-2-2zm0 16H8V7h11v14z"/></svg></button></code></pre><p>对于 timestamp 列，使用其它的分区表达式是不允许的。</p><p>Range 分区在下列条件之一或者多个都满足时，尤其有效：</p><ul><li>删除旧数据。如果你使用之前的 <code>employees</code> 表的例子，你可以简单使用 <code>ALTER TABLE employees DROP PARTITION p0;</code> 删除所有在 1991 年以前停止继续在这家公司工作的员工记录。这会比使用 <code>DELETE FROM employees WHERE YEAR(separated) &lt;= 1990;</code> 执行快得多。</li><li>使用包含时间或者日期的列，或者是其它按序生成的数据。</li><li>频繁查询分区使用的列。例如执行这样的查询 <code>EXPLAIN SELECT COUNT(*) FROM employees WHERE separated BETWEEN '2000-01-01' AND '2000-12-31' GROUP BY store_id;</code> 时，TiDB 可以迅速确定，只需要扫描 <code>p2</code> 分区的数据，因为其它的分区不满足 <code>where</code> 条件。</li></ul><h3 id="range-columns-分区" style="position:relative"><a href="#range-columns-%E5%88%86%E5%8C%BA" aria-label="range columns 分区 permalink" class="anchor before"><svg aria-hidden="true" focusable="false" height="16" version="1.1" viewbox="0 0 16 16" width="16"><path fill-rule="evenodd" d="M4 9h1v1H4c-1.5 0-3-1.69-3-3.5S2.55 3 4 3h4c1.45 0 3 1.69 3 3.5 0 1.41-.91 2.72-2 3.25V8.59c.58-.45 1-1.27 1-2.09C10 5.22 8.98 4 8 4H4c-.98 0-2 1.22-2 2.5S3 9 4 9zm9-3h-1v1h1c1 0 2 1.22 2 2.5S13.98 12 13 12H9c-.98 0-2-1.22-2-2.5 0-.83.42-1.64 1-2.09V6.25c-1.09.53-2 1.84-2 3.25C6 11.31 7.55 13 9 13h4c1.45 0 3-1.69 3-3.5S14.5 6 13 6z"/></svg></a>Range COLUMNS 分区</h3><p>Range COLUMNS 分区是 Range 分区的一种变体。你可以使用一个或者多个列作为分区键，分区列的数据类型可以是整数 (integer)、字符串（<code>CHAR</code>/<code>VARCHAR</code>），<code>DATE</code> 和 <code>DATETIME</code>。不支持使用任何表达式。</p><p>假设你想要按名字进行分区，并且能够轻松地删除旧的无效数据，那么你可以创建一个表格，如下所示：</p><pre><code class="hljs language-sql"><div class="MuiBox-root css-1qhimia"><span class="hljs-keyword">CREATE</span> <span class="hljs-keyword">TABLE</span> t ( valid_until datetime, name <span class="hljs-type">varchar</span>(<span class="hljs-number">255</span>) <span class="hljs-type">CHARACTER</span> <span class="hljs-keyword">SET</span> ascii, notes text <span class="hljs-keyword">PARTITION</span> <span class="hljs-keyword">BY</span> <span class="hljs-keyword">RANGE</span> COLUMNS(name, valid_until) (<span class="hljs-keyword">PARTITION</span> `p2022<span class="hljs-operator">-</span>g` <span class="hljs-keyword">VALUES</span> LESS THAN (<span class="hljs-string">'G'</span>,<span class="hljs-string">'2023-01-01 00:00:00'</span>), <span class="hljs-keyword">PARTITION</span> `p2023<span class="hljs-operator">-</span>g` <span class="hljs-keyword">VALUES</span> LESS THAN (<span class="hljs-string">'G'</span>,<span class="hljs-string">'2024-01-01 00:00:00'</span>), <span class="hljs-keyword">PARTITION</span> `p2022<span class="hljs-operator">-</span>m` <span class="hljs-keyword">VALUES</span> LESS THAN (<span class="hljs-string">'M'</span>,<span class="hljs-string">'2023-01-01 00:00:00'</span>), <span class="hljs-keyword">PARTITION</span> `p2023<span class="hljs-operator">-</span>m` <span class="hljs-keyword">VALUES</span> LESS THAN (<span class="hljs-string">'M'</span>,<span class="hljs-string">'2024-01-01 00:00:00'</span>), <span class="hljs-keyword">PARTITION</span> `p2022<span class="hljs-operator">-</span>s` <span class="hljs-keyword">VALUES</span> LESS THAN (<span class="hljs-string">'S'</span>,<span class="hljs-string">'2023-01-01 00:00:00'</span>), <span class="hljs-keyword">PARTITION</span> `p2023<span class="hljs-operator">-</span>s` <span class="hljs-keyword">VALUES</span> LESS THAN (<span class="hljs-string">'S'</span>,<span class="hljs-string">'2024-01-01 00:00:00'</span>)) </div><button class="MuiButtonBase-root MuiIconButton-root MuiIconButton-sizeSmall css-1rmx1rm" tabindex="0" type="button" aria-label="Toggle code wrap"><svg class="MuiSvgIcon-root MuiSvgIcon-fontSizeInherit css-1cw4hi4" focusable="false" aria-hidden="true" viewbox="0 0 24 24" data-testid="WrapTextIcon"><path d="M4 19h6v-2H4v2zM20 5H4v2h16V5zm-3 6H4v2h13.25c1.1 0 2 .9 2 2s-.9 2-2 2H15v-2l-3 3 3 3v-2h2c2.21 0 4-1.79 4-4s-1.79-4-4-4z"/></svg></button><button class="MuiButtonBase-root MuiIconButton-root MuiIconButton-sizeSmall css-fxo539" tabindex="0" type="button" aria-label="copy"><svg class="MuiSvgIcon-root MuiSvgIcon-fontSizeInherit css-1cw4hi4" focusable="false" aria-hidden="true" viewbox="0 0 24 24" data-testid="ContentCopyIcon"><path d="M16 1H4c-1.1 0-2 .9-2 2v14h2V3h12V1zm3 4H8c-1.1 0-2 .9-2 2v14c0 1.1.9 2 2 2h11c1.1 0 2-.9 2-2V7c0-1.1-.9-2-2-2zm0 16H8V7h11v14z"/></svg></button></code></pre><p>该语句将按名字和年份的范围 <code>[ ('', ''), ('G', '2023-01-01 00:00:00') )</code>，<code>[ ('G', '2023-01-01 00:00:00'), ('G', '2024-01-01 00:00:00') )</code>，<code>[ ('G', '2024-01-01 00:00:00'), ('M', '2023-01-01 00:00:00') )</code>，<code>[ ('M', '2023-01-01 00:00:00'), ('M', '2024-01-01 00:00:00') )</code>，<code>[ ('M', '2024-01-01 00:00:00'), ('S', '2023-01-01 00:00:00') )</code>，<code>[ ('S', '2023-01-01 00:00:00'), ('S', '2024-01-01 00:00:00') )</code> 进行分区，删除无效数据，同时仍然可以在 name 和 valid_until 列上进行分区裁剪。其中，<code>[,)</code> 是一个左闭右开区间，比如 <code>[ ('G', '2023-01-01 00:00:00'), ('G', '2024-01-01 00:00:00') )</code>，表示 name 为 <code>'G'</code> ，年份包含 2023-01-01 00:00:00 并大于 2023-01-01 00:00:00 但小于 2024-01-01 00:00:00 的数据，其中不包含 <code>(G, 2024-01-01 00:00:00)</code>。</p><h3 id="range-interval-分区" style="position:relative"><a href="#range-interval-%E5%88%86%E5%8C%BA" aria-label="range interval 分区 permalink" class="anchor before"><svg aria-hidden="true" focusable="false" height="16" version="1.1" viewbox="0 0 16 16" width="16"><path fill-rule="evenodd" d="M4 9h1v1H4c-1.5 0-3-1.69-3-3.5S2.55 3 4 3h4c1.45 0 3 1.69 3 3.5 0 1.41-.91 2.72-2 3.25V8.59c.58-.45 1-1.27 1-2.09C10 5.22 8.98 4 8 4H4c-.98 0-2 1.22-2 2.5S3 9 4 9zm9-3h-1v1h1c1 0 2 1.22 2 2.5S13.98 12 13 12H9c-.98 0-2-1.22-2-2.5 0-.83.42-1.64 1-2.09V6.25c-1.09.53-2 1.84-2 3.25C6 11.31 7.55 13 9 13h4c1.45 0 3-1.69 3-3.5S14.5 6 13 6z"/></svg></a>Range INTERVAL 分区</h3><p>TiDB v6.3.0 新增了 Range INTERVAL 分区特性，作为语法糖（syntactic sugar）引入。Range INTERVAL 分区是对 Range 分区的扩展。你可以使用特定的间隔（interval）轻松创建分区。</p><p>其语法如下：</p><pre><code class="hljs language-sql"><div class="MuiBox-root css-1qhimia"><span class="hljs-keyword">PARTITION</span> <span class="hljs-keyword">BY</span> <span class="hljs-keyword">RANGE</span> [COLUMNS] (<span class="hljs-operator">&lt;</span>partitioning expression<span class="hljs-operator">&gt;</span>) <span class="hljs-type">INTERVAL</span> (<span class="hljs-operator">&lt;</span><span class="hljs-type">interval</span> expression<span class="hljs-operator">&gt;</span>) <span class="hljs-keyword">FIRST</span> <span class="hljs-keyword">PARTITION</span> LESS THAN (<span class="hljs-operator">&lt;</span>expression<span class="hljs-operator">&gt;</span>) <span class="hljs-keyword">LAST</span> <span class="hljs-keyword">PARTITION</span> LESS THAN (<span class="hljs-operator">&lt;</span>expression<span class="hljs-operator">&gt;</span>) [<span class="hljs-keyword">NULL</span> <span class="hljs-keyword">PARTITION</span>] [MAXVALUE <span class="hljs-keyword">PARTITION</span>] </div><button class="MuiButtonBase-root MuiIconButton-root MuiIconButton-sizeSmall css-1rmx1rm" tabindex="0" type="button" aria-label="Toggle code wrap"><svg class="MuiSvgIcon-root MuiSvgIcon-fontSizeInherit css-1cw4hi4" focusable="false" aria-hidden="true" viewbox="0 0 24 24" data-testid="WrapTextIcon"><path d="M4 19h6v-2H4v2zM20 5H4v2h16V5zm-3 6H4v2h13.25c1.1 0 2 .9 2 2s-.9 2-2 2H15v-2l-3 3 3 3v-2h2c2.21 0 4-1.79 4-4s-1.79-4-4-4z"/></svg></button><button class="MuiButtonBase-root MuiIconButton-root MuiIconButton-sizeSmall css-fxo539" tabindex="0" type="button" aria-label="copy"><svg class="MuiSvgIcon-root MuiSvgIcon-fontSizeInherit css-1cw4hi4" focusable="false" aria-hidden="true" viewbox="0 0 24 24" data-testid="ContentCopyIcon"><path d="M16 1H4c-1.1 0-2 .9-2 2v14h2V3h12V1zm3 4H8c-1.1 0-2 .9-2 2v14c0 1.1.9 2 2 2h11c1.1 0 2-.9 2-2V7c0-1.1-.9-2-2-2zm0 16H8V7h11v14z"/></svg></button></code></pre><p>示例：</p><pre><code class="hljs language-sql"><div class="MuiBox-root css-1qhimia"><span class="hljs-keyword">CREATE</span> <span class="hljs-keyword">TABLE</span> employees ( id <span class="hljs-type">int</span> unsigned <span class="hljs-keyword">NOT</span> <span class="hljs-keyword">NULL</span>, fname <span class="hljs-type">varchar</span>(<span class="hljs-number">30</span>), lname <span class="hljs-type">varchar</span>(<span class="hljs-number">30</span>), hired <span class="hljs-type">date</span> <span class="hljs-keyword">NOT</span> <span class="hljs-keyword">NULL</span> <span class="hljs-keyword">DEFAULT</span> <span class="hljs-string">'1970-01-01'</span>, separated <span class="hljs-type">date</span> <span class="hljs-keyword">DEFAULT</span> <span class="hljs-string">'9999-12-31'</span>, job_code <span class="hljs-type">int</span>, store_id <span class="hljs-type">int</span> <span class="hljs-keyword">NOT</span> <span class="hljs-keyword">NULL</span> ) <span class="hljs-keyword">PARTITION</span> <span class="hljs-keyword">BY</span> <span class="hljs-keyword">RANGE</span> (id) <span class="hljs-type">INTERVAL</span> (<span class="hljs-number">100</span>) <span class="hljs-keyword">FIRST</span> <span class="hljs-keyword">PARTITION</span> LESS THAN (<span class="hljs-number">100</span>) <span class="hljs-keyword">LAST</span> <span class="hljs-keyword">PARTITION</span> LESS THAN (<span class="hljs-number">10000</span>) MAXVALUE <span class="hljs-keyword">PARTITION</span> </div><button class="MuiButtonBase-root MuiIconButton-root MuiIconButton-sizeSmall css-1rmx1rm" tabindex="0" type="button" aria-label="Toggle code wrap"><svg class="MuiSvgIcon-root MuiSvgIcon-fontSizeInherit css-1cw4hi4" focusable="false" aria-hidden="true" viewbox="0 0 24 24" data-testid="WrapTextIcon"><path d="M4 19h6v-2H4v2zM20 5H4v2h16V5zm-3 6H4v2h13.25c1.1 0 2 .9 2 2s-.9 2-2 2H15v-2l-3 3 3 3v-2h2c2.21 0 4-1.79 4-4s-1.79-4-4-4z"/></svg></button><button class="MuiButtonBase-root MuiIconButton-root MuiIconButton-sizeSmall css-fxo539" tabindex="0" type="button" aria-label="copy"><svg class="MuiSvgIcon-root MuiSvgIcon-fontSizeInherit css-1cw4hi4" focusable="false" aria-hidden="true" viewbox="0 0 24 24" data-testid="ContentCopyIcon"><path d="M16 1H4c-1.1 0-2 .9-2 2v14h2V3h12V1zm3 4H8c-1.1 0-2 .9-2 2v14c0 1.1.9 2 2 2h11c1.1 0 2-.9 2-2V7c0-1.1-.9-2-2-2zm0 16H8V7h11v14z"/></svg></button></code></pre><p>该示例创建的表与如下 SQL 语句相同：</p><pre><code class="hljs language-sql"><div class="MuiBox-root css-1qhimia"><span class="hljs-keyword">CREATE</span> <span class="hljs-keyword">TABLE</span> `employees` ( `id` <span class="hljs-type">int</span> unsigned <span class="hljs-keyword">NOT</span> <span class="hljs-keyword">NULL</span>, `fname` <span class="hljs-type">varchar</span>(<span class="hljs-number">30</span>) <span class="hljs-keyword">DEFAULT</span> <span class="hljs-keyword">NULL</span>, `lname` <span class="hljs-type">varchar</span>(<span class="hljs-number">30</span>) <span class="hljs-keyword">DEFAULT</span> <span class="hljs-keyword">NULL</span>, `hired` <span class="hljs-type">date</span> <span class="hljs-keyword">NOT</span> <span class="hljs-keyword">NULL</span> <span class="hljs-keyword">DEFAULT</span> <span class="hljs-string">'1970-01-01'</span>, `separated` <span class="hljs-type">date</span> <span class="hljs-keyword">DEFAULT</span> <span class="hljs-string">'9999-12-31'</span>, `job_code` <span class="hljs-type">int</span> <span class="hljs-keyword">DEFAULT</span> <span class="hljs-keyword">NULL</span>, `store_id` <span class="hljs-type">int</span> <span class="hljs-keyword">NOT</span> <span class="hljs-keyword">NULL</span> <span class="hljs-keyword">PARTITION</span> <span class="hljs-keyword">BY</span> <span class="hljs-keyword">RANGE</span> (`id`) (<span class="hljs-keyword">PARTITION</span> `P_LT_100` <span class="hljs-keyword">VALUES</span> LESS THAN (<span class="hljs-number">100</span>), <span class="hljs-keyword">PARTITION</span> `P_LT_200` <span class="hljs-keyword">VALUES</span> LESS THAN (<span class="hljs-number">200</span>), <span class="hljs-keyword">PARTITION</span> `P_LT_9900` <span class="hljs-keyword">VALUES</span> LESS THAN (<span class="hljs-number">9900</span>), <span class="hljs-keyword">PARTITION</span> `P_LT_10000` <span class="hljs-keyword">VALUES</span> LESS THAN (<span class="hljs-number">10000</span>), <span class="hljs-keyword">PARTITION</span> `P_MAXVALUE` <span class="hljs-keyword">VALUES</span> LESS THAN (MAXVALUE)) </div><button class="MuiButtonBase-root MuiIconButton-root MuiIconButton-sizeSmall css-1rmx1rm" tabindex="0" type="button" aria-label="Toggle code wrap"><svg class="MuiSvgIcon-root MuiSvgIcon-fontSizeInherit css-1cw4hi4" focusable="false" aria-hidden="true" viewbox="0 0 24 24" data-testid="WrapTextIcon"><path d="M4 19h6v-2H4v2zM20 5H4v2h16V5zm-3 6H4v2h13.25c1.1 0 2 .9 2 2s-.9 2-2 2H15v-2l-3 3 3 3v-2h2c2.21 0 4-1.79 4-4s-1.79-4-4-4z"/></svg></button><button class="MuiButtonBase-root MuiIconButton-root MuiIconButton-sizeSmall css-fxo539" tabindex="0" type="button" aria-label="copy"><svg class="MuiSvgIcon-root MuiSvgIcon-fontSizeInherit css-1cw4hi4" focusable="false" aria-hidden="true" viewbox="0 0 24 24" data-testid="ContentCopyIcon"><path d="M16 1H4c-1.1 0-2 .9-2 2v14h2V3h12V1zm3 4H8c-1.1 0-2 .9-2 2v14c0 1.1.9 2 2 2h11c1.1 0 2-.9 2-2V7c0-1.1-.9-2-2-2zm0 16H8V7h11v14z"/></svg></button></code></pre><p>Range INTERVAL 还可以配合 <a href="#range-columns-%E5%88%86%E5%8C%BA">Range COLUMNS</a> 分区一起使用。如下面的示例：</p><pre><code class="hljs language-sql"><div class="MuiBox-root css-1qhimia"><span class="hljs-keyword">CREATE</span> <span class="hljs-keyword">TABLE</span> monthly_report_status ( report_id <span class="hljs-type">int</span> <span class="hljs-keyword">NOT</span> <span class="hljs-keyword">NULL</span>, report_status <span class="hljs-type">varchar</span>(<span class="hljs-number">20</span>) <span class="hljs-keyword">NOT</span> <span class="hljs-keyword">NULL</span>, report_date <span class="hljs-type">date</span> <span class="hljs-keyword">NOT</span> <span class="hljs-keyword">NULL</span> <span class="hljs-keyword">PARTITION</span> <span class="hljs-keyword">BY</span> <span class="hljs-keyword">RANGE</span> COLUMNS (report_date) <span class="hljs-type">INTERVAL</span> (<span class="hljs-number">1</span> <span class="hljs-keyword">MONTH</span>) <span class="hljs-keyword">FIRST</span> <span class="hljs-keyword">PARTITION</span> LESS THAN (<span class="hljs-string">'2000-01-01'</span>) <span class="hljs-keyword">LAST</span> <span class="hljs-keyword">PARTITION</span> LESS THAN (<span class="hljs-string">'2025-01-01'</span>) </div><button class="MuiButtonBase-root MuiIconButton-root MuiIconButton-sizeSmall css-1rmx1rm" tabindex="0" type="button" aria-label="Toggle code wrap"><svg class="MuiSvgIcon-root MuiSvgIcon-fontSizeInherit css-1cw4hi4" focusable="false" aria-hidden="true" viewbox="0 0 24 24" data-testid="WrapTextIcon"><path d="M4 19h6v-2H4v2zM20 5H4v2h16V5zm-3 6H4v2h13.25c1.1 0 2 .9 2 2s-.9 2-2 2H15v-2l-3 3 3 3v-2h2c2.21 0 4-1.79 4-4s-1.79-4-4-4z"/></svg></button><button class="MuiButtonBase-root MuiIconButton-root MuiIconButton-sizeSmall css-fxo539" tabindex="0" type="button" aria-label="copy"><svg class="MuiSvgIcon-root MuiSvgIcon-fontSizeInherit css-1cw4hi4" focusable="false" aria-hidden="true" viewbox="0 0 24 24" data-testid="ContentCopyIcon"><path d="M16 1H4c-1.1 0-2 .9-2 2v14h2V3h12V1zm3 4H8c-1.1 0-2 .9-2 2v14c0 1.1.9 2 2 2h11c1.1 0 2-.9 2-2V7c0-1.1-.9-2-2-2zm0 16H8V7h11v14z"/></svg></button></code></pre><p>该示例创建的表与如下 SQL 语句相同：</p><pre><code class="hljs language-sql"><div class="MuiBox-root css-1qhimia"><span class="hljs-keyword">CREATE</span> <span class="hljs-keyword">TABLE</span> `monthly_report_status` ( `report_id` <span class="hljs-type">int</span>(<span class="hljs-number">11</span>) <span class="hljs-keyword">NOT</span> <span class="hljs-keyword">NULL</span>, `report_status` <span class="hljs-type">varchar</span>(<span class="hljs-number">20</span>) <span class="hljs-keyword">NOT</span> <span class="hljs-keyword">NULL</span>, `report_date` <span class="hljs-type">date</span> <span class="hljs-keyword">NOT</span> <span class="hljs-keyword">NULL</span> ) ENGINE<span class="hljs-operator">=</span>InnoDB <span class="hljs-keyword">DEFAULT</span> CHARSET<span class="hljs-operator">=</span>utf8mb4 <span class="hljs-keyword">COLLATE</span><span class="hljs-operator">=</span>utf8mb4_bin <span class="hljs-keyword">PARTITION</span> <span class="hljs-keyword">BY</span> <span class="hljs-keyword">RANGE</span> COLUMNS(`report_date`) (<span class="hljs-keyword">PARTITION</span> `P_LT_2000<span class="hljs-number">-01</span><span class="hljs-number">-01</span>` <span class="hljs-keyword">VALUES</span> LESS THAN (<span class="hljs-string">'2000-01-01'</span>), <span class="hljs-keyword">PARTITION</span> `P_LT_2000<span class="hljs-number">-02</span><span class="hljs-number">-01</span>` <span class="hljs-keyword">VALUES</span> LESS THAN (<span class="hljs-string">'2000-02-01'</span>), <span class="hljs-keyword">PARTITION</span> `P_LT_2024<span class="hljs-number">-11</span><span class="hljs-number">-01</span>` <span class="hljs-keyword">VALUES</span> LESS THAN (<span class="hljs-string">'2024-11-01'</span>), <span class="hljs-keyword">PARTITION</span> `P_LT_2024<span class="hljs-number">-12</span><span class="hljs-number">-01</span>` <span class="hljs-keyword">VALUES</span> LESS THAN (<span class="hljs-string">'2024-12-01'</span>), <span class="hljs-keyword">PARTITION</span> `P_LT_2025<span class="hljs-number">-01</span><span class="hljs-number">-01</span>` <span class="hljs-keyword">VALUES</span> LESS THAN (<span class="hljs-string">'2025-01-01'</span>)) </div><button class="MuiButtonBase-root MuiIconButton-root MuiIconButton-sizeSmall css-1rmx1rm" tabindex="0" type="button" aria-label="Toggle code wrap"><svg class="MuiSvgIcon-root MuiSvgIcon-fontSizeInherit css-1cw4hi4" focusable="false" aria-hidden="true" viewbox="0 0 24 24" data-testid="WrapTextIcon"><path d="M4 19h6v-2H4v2zM20 5H4v2h16V5zm-3 6H4v2h13.25c1.1 0 2 .9 2 2s-.9 2-2 2H15v-2l-3 3 3 3v-2h2c2.21 0 4-1.79 4-4s-1.79-4-4-4z"/></svg></button><button class="MuiButtonBase-root MuiIconButton-root MuiIconButton-sizeSmall css-fxo539" tabindex="0" type="button" aria-label="copy"><svg class="MuiSvgIcon-root MuiSvgIcon-fontSizeInherit css-1cw4hi4" focusable="false" aria-hidden="true" viewbox="0 0 24 24" data-testid="ContentCopyIcon"><path d="M16 1H4c-1.1 0-2 .9-2 2v14h2V3h12V1zm3 4H8c-1.1 0-2 .9-2 2v14c0 1.1.9 2 2 2h11c1.1 0 2-.9 2-2V7c0-1.1-.9-2-2-2zm0 16H8V7h11v14z"/></svg></button></code></pre><p>可选参数 <code>NULL PARTITION</code> 会创建一个分区，其中分区表达式推导出的值为 <code>NULL</code> 的数据会放到该分区。在分区表达式中，<code>NULL</code> 会被认为是小于任何其他值。参见<a href="#range-%E5%88%86%E5%8C%BA%E5%AF%B9-null-%E7%9A%84%E5%A4%84%E7%90%86">分区对 NULL 值的处理</a>。</p><p>可选参数 <code>MAXVALUE PARTITION</code> 会创建一个最后的分区，其值为 <code>PARTITION P_MAXVALUE VALUES LESS THAN (MAXVALUE)</code>。</p><h4 id="alter-interval-分区" style="position:relative"><a href="#alter-interval-%E5%88%86%E5%8C%BA" aria-label="alter interval 分区 permalink" class="anchor before"><svg aria-hidden="true" focusable="false" height="16" version="1.1" viewbox="0 0 16 16" width="16"><path fill-rule="evenodd" d="M4 9h1v1H4c-1.5 0-3-1.69-3-3.5S2.55 3 4 3h4c1.45 0 3 1.69 3 3.5 0 1.41-.91 2.72-2 3.25V8.59c.58-.45 1-1.27 1-2.09C10 5.22 8.98 4 8 4H4c-.98 0-2 1.22-2 2.5S3 9 4 9zm9-3h-1v1h1c1 0 2 1.22 2 2.5S13.98 12 13 12H9c-.98 0-2-1.22-2-2.5 0-.83.42-1.64 1-2.09V6.25c-1.09.53-2 1.84-2 3.25C6 11.31 7.55 13 9 13h4c1.45 0 3-1.69 3-3.5S14.5 6 13 6z"/></svg></a>ALTER INTERVAL 分区</h4><p>INTERVAL 分区还增加了添加和删除分区的更加简单易用的语法。</p><p>下面的语句会变更第一个分区，该语句会删除所有小于给定表达式的分区，使匹配的分区成为新的第一个分区。它不会影响 <code>NULL PARTITION</code>。</p><pre><code class="hljs language-sql"><div class="MuiBox-root css-1qhimia"><span class="hljs-keyword">ALTER</span> <span class="hljs-keyword">TABLE</span> table_name <span class="hljs-keyword">FIRST</span> <span class="hljs-keyword">PARTITION</span> LESS THAN (<span class="hljs-operator">&lt;</span>expression<span class="hljs-operator">&gt;</span>) </div><button class="MuiButtonBase-root MuiIconButton-root MuiIconButton-sizeSmall css-1rmx1rm" tabindex="0" type="button" aria-label="Toggle code wrap"><svg class="MuiSvgIcon-root MuiSvgIcon-fontSizeInherit css-1cw4hi4" focusable="false" aria-hidden="true" viewbox="0 0 24 24" data-testid="WrapTextIcon"><path d="M4 19h6v-2H4v2zM20 5H4v2h16V5zm-3 6H4v2h13.25c1.1 0 2 .9 2 2s-.9 2-2 2H15v-2l-3 3 3 3v-2h2c2.21 0 4-1.79 4-4s-1.79-4-4-4z"/></svg></button><button class="MuiButtonBase-root MuiIconButton-root MuiIconButton-sizeSmall css-fxo539" tabindex="0" type="button" aria-label="copy"><svg class="MuiSvgIcon-root MuiSvgIcon-fontSizeInherit css-1cw4hi4" focusable="false" aria-hidden="true" viewbox="0 0 24 24" data-testid="ContentCopyIcon"><path d="M16 1H4c-1.1 0-2 .9-2 2v14h2V3h12V1zm3 4H8c-1.1 0-2 .9-2 2v14c0 1.1.9 2 2 2h11c1.1 0 2-.9 2-2V7c0-1.1-.9-2-2-2zm0 16H8V7h11v14z"/></svg></button></code></pre><p>下面的语句会变更最后一个分区，该语句会添加新的分区，分区范围扩大到给定的表达式的值。如果存在 <code>MAXVALUE PARTITION</code>，则该语句不会生效，因为它需要数据重组。</p><pre><code class="hljs language-sql"><div class="MuiBox-root css-1qhimia"><span class="hljs-keyword">ALTER</span> <span class="hljs-keyword">TABLE</span> table_name <span class="hljs-keyword">LAST</span> <span class="hljs-keyword">PARTITION</span> LESS THAN (<span class="hljs-operator">&lt;</span>expression<span class="hljs-operator">&gt;</span>) </div><button class="MuiButtonBase-root MuiIconButton-root MuiIconButton-sizeSmall css-1rmx1rm" tabindex="0" type="button" aria-label="Toggle code wrap"><svg class="MuiSvgIcon-root MuiSvgIcon-fontSizeInherit css-1cw4hi4" focusable="false" aria-hidden="true" viewbox="0 0 24 24" data-testid="WrapTextIcon"><path d="M4 19h6v-2H4v2zM20 5H4v2h16V5zm-3 6H4v2h13.25c1.1 0 2 .9 2 2s-.9 2-2 2H15v-2l-3 3 3 3v-2h2c2.21 0 4-1.79 4-4s-1.79-4-4-4z"/></svg></button><button class="MuiButtonBase-root MuiIconButton-root MuiIconButton-sizeSmall css-fxo539" tabindex="0" type="button" aria-label="copy"><svg class="MuiSvgIcon-root MuiSvgIcon-fontSizeInherit css-1cw4hi4" focusable="false" aria-hidden="true" viewbox="0 0 24 24" data-testid="ContentCopyIcon"><path d="M16 1H4c-1.1 0-2 .9-2 2v14h2V3h12V1zm3 4H8c-1.1 0-2 .9-2 2v14c0 1.1.9 2 2 2h11c1.1 0 2-.9 2-2V7c0-1.1-.9-2-2-2zm0 16H8V7h11v14z"/></svg></button></code></pre><h4 id="interval-分区相关细节和限制" style="position:relative"><a href="#interval-%E5%88%86%E5%8C%BA%E7%9B%B8%E5%85%B3%E7%BB%86%E8%8A%82%E5%92%8C%E9%99%90%E5%88%B6" aria-label="interval 分区相关细节和限制 permalink" class="anchor before"><svg aria-hidden="true" focusable="false" height="16" version="1.1" viewbox="0 0 16 16" width="16"><path fill-rule="evenodd" d="M4 9h1v1H4c-1.5 0-3-1.69-3-3.5S2.55 3 4 3h4c1.45 0 3 1.69 3 3.5 0 1.41-.91 2.72-2 3.25V8.59c.58-.45 1-1.27 1-2.09C10 5.22 8.98 4 8 4H4c-.98 0-2 1.22-2 2.5S3 9 4 9zm9-3h-1v1h1c1 0 2 1.22 2 2.5S13.98 12 13 12H9c-.98 0-2-1.22-2-2.5 0-.83.42-1.64 1-2.09V6.25c-1.09.53-2 1.84-2 3.25C6 11.31 7.55 13 9 13h4c1.45 0 3-1.69 3-3.5S14.5 6 13 6z"/></svg></a>INTERVAL 分区相关细节和限制</h4><ul><li>INTERVAL 分区特性仅涉及 <code>CREATE/ALTER TABLE</code> 语法。元数据保持不变，因此使用该新语法创建或变更的表仍然兼容 MySQL。</li><li>为保持兼容 MySQL，<code>SHOW CREATE TABLE</code> 的输出格式保持不变。</li><li>遵循 INTERVAL 的存量表可以使用新的 <code>ALTER</code> 语法。不需要使用 <code>INTERVAL</code> 语法重新创建这些表。</li><li>对于 <code>RANGE COLUMNS</code>，仅支持整数 (INTEGER) 类型、日期 (DATE) 和日期时间 (DATETIME) 列类型。</li></ul><h3 id="list-分区" style="position:relative"><a href="#list-%E5%88%86%E5%8C%BA" aria-label="list 分区 permalink" class="anchor before"><svg aria-hidden="true" focusable="false" height="16" version="1.1" viewbox="0 0 16 16" width="16"><path fill-rule="evenodd" d="M4 9h1v1H4c-1.5 0-3-1.69-3-3.5S2.55 3 4 3h4c1.45 0 3 1.69 3 3.5 0 1.41-.91 2.72-2 3.25V8.59c.58-.45 1-1.27 1-2.09C10 5.22 8.98 4 8 4H4c-.98 0-2 1.22-2 2.5S3 9 4 9zm9-3h-1v1h1c1 0 2 1.22 2 2.5S13.98 12 13 12H9c-.98 0-2-1.22-2-2.5 0-.83.42-1.64 1-2.09V6.25c-1.09.53-2 1.84-2 3.25C6 11.31 7.55 13 9 13h4c1.45 0 3-1.69 3-3.5S14.5 6 13 6z"/></svg></a>List 分区</h3><p>在创建 List 分区表之前，请确保以下系统变量为其默认值 <code>ON</code>：</p><ul><li><a href="/zh/tidb/stable/system-variables#tidb_enable_list_partition-从-v50-版本开始引入"><code>tidb_enable_list_partition</code></a> </li><li><a href="/zh/tidb/stable/system-variables#tidb_enable_table_partition"><code>tidb_enable_table_partition</code></a> </li></ul><p>List 分区和 Range 分区有很多相似的地方。不同之处主要在于 List 分区中，对于表的每个分区中包含的所有行，按分区表达式计算的值属于给定的数据集合。每个分区定义的数据集合有任意个值，但不能有重复的值，可通过 <code>PARTITION ... VALUES IN (...)</code> 子句对值进行定义。</p><p>假设你要创建一张人事记录表，示例如下：</p><pre><code class="hljs language-sql"><div class="MuiBox-root css-1qhimia"><span class="hljs-keyword">CREATE</span> <span class="hljs-keyword">TABLE</span> employees ( id <span class="hljs-type">INT</span> <span class="hljs-keyword">NOT</span> <span class="hljs-keyword">NULL</span>, hired <span class="hljs-type">DATE</span> <span class="hljs-keyword">NOT</span> <span class="hljs-keyword">NULL</span> <span class="hljs-keyword">DEFAULT</span> <span class="hljs-string">'1970-01-01'</span>, store_id <span class="hljs-type">INT</span> </div><button class="MuiButtonBase-root MuiIconButton-root MuiIconButton-sizeSmall css-1rmx1rm" tabindex="0" type="button" aria-label="Toggle code wrap"><svg class="MuiSvgIcon-root MuiSvgIcon-fontSizeInherit css-1cw4hi4" focusable="false" aria-hidden="true" viewbox="0 0 24 24" data-testid="WrapTextIcon"><path d="M4 19h6v-2H4v2zM20 5H4v2h16V5zm-3 6H4v2h13.25c1.1 0 2 .9 2 2s-.9 2-2 2H15v-2l-3 3 3 3v-2h2c2.21 0 4-1.79 4-4s-1.79-4-4-4z"/></svg></button><button class="MuiButtonBase-root MuiIconButton-root MuiIconButton-sizeSmall css-fxo539" tabindex="0" type="button" aria-label="copy"><svg class="MuiSvgIcon-root MuiSvgIcon-fontSizeInherit css-1cw4hi4" focusable="false" aria-hidden="true" viewbox="0 0 24 24" data-testid="ContentCopyIcon"><path d="M16 1H4c-1.1 0-2 .9-2 2v14h2V3h12V1zm3 4H8c-1.1 0-2 .9-2 2v14c0 1.1.9 2 2 2h11c1.1 0 2-.9 2-2V7c0-1.1-.9-2-2-2zm0 16H8V7h11v14z"/></svg></button></code></pre><p>假如一共有 20 个商店分布在 4 个地区，如下表所示：</p><pre><code class="hljs language-"><div class="MuiBox-root css-1qhimia">| Region | Store ID Numbers | | ------- | -------------------- | | North | 1, 2, 3, 4, 5 | | East | 6, 7, 8, 9, 10 | | West | 11, 12, 13, 14, 15 | | Central | 16, 17, 18, 19, 20 | </div><button class="MuiButtonBase-root MuiIconButton-root MuiIconButton-sizeSmall css-1rmx1rm" tabindex="0" type="button" aria-label="Toggle code wrap"><svg class="MuiSvgIcon-root MuiSvgIcon-fontSizeInherit css-1cw4hi4" focusable="false" aria-hidden="true" viewbox="0 0 24 24" data-testid="WrapTextIcon"><path d="M4 19h6v-2H4v2zM20 5H4v2h16V5zm-3 6H4v2h13.25c1.1 0 2 .9 2 2s-.9 2-2 2H15v-2l-3 3 3 3v-2h2c2.21 0 4-1.79 4-4s-1.79-4-4-4z"/></svg></button><button class="MuiButtonBase-root MuiIconButton-root MuiIconButton-sizeSmall css-fxo539" tabindex="0" type="button" aria-label="copy"><svg class="MuiSvgIcon-root MuiSvgIcon-fontSizeInherit css-1cw4hi4" focusable="false" aria-hidden="true" viewbox="0 0 24 24" data-testid="ContentCopyIcon"><path d="M16 1H4c-1.1 0-2 .9-2 2v14h2V3h12V1zm3 4H8c-1.1 0-2 .9-2 2v14c0 1.1.9 2 2 2h11c1.1 0 2-.9 2-2V7c0-1.1-.9-2-2-2zm0 16H8V7h11v14z"/></svg></button></code></pre><p>如果想把同一个地区商店员工的人事数据都存储在同一个分区中，你可以根据 <code>store_id</code> 来创建 List 分区：</p><pre><code class="hljs language-sql"><div class="MuiBox-root css-1qhimia"><span class="hljs-keyword">CREATE</span> <span class="hljs-keyword">TABLE</span> employees ( id <span class="hljs-type">INT</span> <span class="hljs-keyword">NOT</span> <span class="hljs-keyword">NULL</span>, hired <span class="hljs-type">DATE</span> <span class="hljs-keyword">NOT</span> <span class="hljs-keyword">NULL</span> <span class="hljs-keyword">DEFAULT</span> <span class="hljs-string">'1970-01-01'</span>, store_id <span class="hljs-type">INT</span> <span class="hljs-keyword">PARTITION</span> <span class="hljs-keyword">BY</span> LIST (store_id) ( <span class="hljs-keyword">PARTITION</span> pNorth <span class="hljs-keyword">VALUES</span> <span class="hljs-keyword">IN</span> (<span class="hljs-number">1</span>, <span class="hljs-number">2</span>, <span class="hljs-number">3</span>, <span class="hljs-number">4</span>, <span class="hljs-number">5</span>), <span class="hljs-keyword">PARTITION</span> pEast <span class="hljs-keyword">VALUES</span> <span class="hljs-keyword">IN</span> (<span class="hljs-number">6</span>, <span class="hljs-number">7</span>, <span class="hljs-number">8</span>, <span class="hljs-number">9</span>, <span class="hljs-number">10</span>), <span class="hljs-keyword">PARTITION</span> pWest <span class="hljs-keyword">VALUES</span> <span class="hljs-keyword">IN</span> (<span class="hljs-number">11</span>, <span class="hljs-number">12</span>, <span class="hljs-number">13</span>, <span class="hljs-number">14</span>, <span class="hljs-number">15</span>), <span class="hljs-keyword">PARTITION</span> pCentral <span class="hljs-keyword">VALUES</span> <span class="hljs-keyword">IN</span> (<span class="hljs-number">16</span>, <span class="hljs-number">17</span>, <span class="hljs-number">18</span>, <span class="hljs-number">19</span>, <span class="hljs-number">20</span>) </div><button class="MuiButtonBase-root MuiIconButton-root MuiIconButton-sizeSmall css-1rmx1rm" tabindex="0" type="button" aria-label="Toggle code wrap"><svg class="MuiSvgIcon-root MuiSvgIcon-fontSizeInherit css-1cw4hi4" focusable="false" aria-hidden="true" viewbox="0 0 24 24" data-testid="WrapTextIcon"><path d="M4 19h6v-2H4v2zM20 5H4v2h16V5zm-3 6H4v2h13.25c1.1 0 2 .9 2 2s-.9 2-2 2H15v-2l-3 3 3 3v-2h2c2.21 0 4-1.79 4-4s-1.79-4-4-4z"/></svg></button><button class="MuiButtonBase-root MuiIconButton-root MuiIconButton-sizeSmall css-fxo539" tabindex="0" type="button" aria-label="copy"><svg class="MuiSvgIcon-root MuiSvgIcon-fontSizeInherit css-1cw4hi4" focusable="false" aria-hidden="true" viewbox="0 0 24 24" data-testid="ContentCopyIcon"><path d="M16 1H4c-1.1 0-2 .9-2 2v14h2V3h12V1zm3 4H8c-1.1 0-2 .9-2 2v14c0 1.1.9 2 2 2h11c1.1 0 2-.9 2-2V7c0-1.1-.9-2-2-2zm0 16H8V7h11v14z"/></svg></button></code></pre><p>这样就能方便地在表中添加或删除与特定区域相关的记录。例如，假设东部地区 (East) 所有的商店都卖给了另一家公司，所有该地区商店员工相关的行数据都可以通过 <code>ALTER TABLE employees TRUNCATE PARTITION pEast</code> 删除，这比等效的 <code>DELETE</code> 语句 <code>DELETE FROM employees WHERE store_id IN (6, 7, 8, 9, 10)</code> 执行起来更加高效。</p><p>使用 <code>ALTER TABLE employees DROP PARTITION pEast</code> 也能删除所有这些行，但同时也会从表的定义中删除分区 <code>pEast</code>。那样你还需要使用 <code>ALTER TABLE ... ADD PARTITION</code> 语句来还原表的原始分区方案。</p><h4 id="默认的-list-分区" style="position:relative"><a href="#%E9%BB%98%E8%AE%A4%E7%9A%84-list-%E5%88%86%E5%8C%BA" aria-label="默认的 list 分区 permalink" class="anchor before"><svg aria-hidden="true" focusable="false" height="16" version="1.1" viewbox="0 0 16 16" width="16"><path fill-rule="evenodd" d="M4 9h1v1H4c-1.5 0-3-1.69-3-3.5S2.55 3 4 3h4c1.45 0 3 1.69 3 3.5 0 1.41-.91 2.72-2 3.25V8.59c.58-.45 1-1.27 1-2.09C10 5.22 8.98 4 8 4H4c-.98 0-2 1.22-2 2.5S3 9 4 9zm9-3h-1v1h1c1 0 2 1.22 2 2.5S13.98 12 13 12H9c-.98 0-2-1.22-2-2.5 0-.83.42-1.64 1-2.09V6.25c-1.09.53-2 1.84-2 3.25C6 11.31 7.55 13 9 13h4c1.45 0 3-1.69 3-3.5S14.5 6 13 6z"/></svg></a>默认的 List 分区</h4><p>从 v7.3.0 版本开始，你可以为 List 或者 List COLUMNS 分区表添加默认的 List 分区。默认的 List 分区作为一个后备分区，可以存储那些不匹配任何分区数据集合的行。</p><style data-emotion="css 1weqspv">.css-1weqspv{padding-top:0.5rem;padding-bottom:0.5rem;}.css-1weqspv .MuiAlert-message p{margin-bottom:0px;margin-top:0px;}</style><div class="MuiBox-root css-1weqspv"><style data-emotion="css 17zlexa">.css-17zlexa{font-size:0.875rem;line-height:1.25rem;font-family:"Helvetica Neue","sans-serif";font-weight:400;font-style:normal;color:rgb(1, 67, 97);background-color:rgb(229, 246, 253);display:-webkit-box;display:-webkit-flex;display:-ms-flexbox;display:flex;padding:6px 16px;}.css-17zlexa .MuiAlert-icon{color:#03a9f4;}</style><style data-emotion="css 152gid5">.css-152gid5{background-color:#fff;color:rgba(0, 0, 0, 0.87);-webkit-transition:box-shadow 300ms cubic-bezier(0.4, 0, 0.2, 1) 0ms;transition:box-shadow 300ms cubic-bezier(0.4, 0, 0.2, 1) 0ms;border-radius:4px;box-shadow:none;font-size:0.875rem;line-height:1.25rem;font-family:"Helvetica Neue","sans-serif";font-weight:400;font-style:normal;color:rgb(1, 67, 97);background-color:rgb(229, 246, 253);display:-webkit-box;display:-webkit-flex;display:-ms-flexbox;display:flex;padding:6px 16px;}.css-152gid5 .MuiAlert-icon{color:#03a9f4;}</style><div class="MuiPaper-root MuiPaper-elevation MuiPaper-rounded MuiPaper-elevation0 MuiAlert-root MuiAlert-standardInfo MuiAlert-standard css-152gid5" role="alert"><style data-emotion="css 1l54tgj">.css-1l54tgj{margin-right:12px;padding:7px 0;display:-webkit-box;display:-webkit-flex;display:-ms-flexbox;display:flex;font-size:22px;opacity:0.9;}</style><div class="MuiAlert-icon css-1l54tgj"><svg class="MuiSvgIcon-root MuiSvgIcon-fontSizeInherit css-1cw4hi4" focusable="false" aria-hidden="true" viewbox="0 0 24 24" data-testid="InfoOutlinedIcon"><path d="M11,9H13V7H11M12,20C7.59,20 4,16.41 4,12C4,7.59 7.59,4 12,4C16.41,4 20,7.59 20, 12C20,16.41 16.41,20 12,20M12,2A10,10 0 0,0 2,12A10,10 0 0,0 12,22A10,10 0 0,0 22,12A10, 10 0 0,0 12,2M11,17H13V11H11V17Z"/></svg></div><style data-emotion="css 1xsto0d">.css-1xsto0d{padding:8px 0;min-width:0;overflow:auto;}</style><div class="MuiAlert-message css-1xsto0d"><style data-emotion="css 1h2y6o4">.css-1h2y6o4{font-weight:500;margin-top:-2px;}</style><style data-emotion="css 17ioyuk">.css-17ioyuk{margin:0;font-size:1rem;line-height:1.5rem;font-family:"Helvetica Neue","sans-serif";font-weight:400;font-style:normal;color:#666666;margin-bottom:0.35em;font-weight:500;margin-top:-2px;}</style><div class="MuiTypography-root MuiTypography-body1 MuiTypography-gutterBottom MuiAlertTitle-root css-17ioyuk">注意</div><p>该功能是 TiDB 对 MySQL 语法的扩展。为 List 或 List COLUMNS 分区表添加默认分区后，该分区表的数据无法直接同步到 MySQL 中。</p></div></div></div><p>以下面的 List 分区表为例：</p><pre><code class="hljs language-sql"><div class="MuiBox-root css-1qhimia"><span class="hljs-keyword">CREATE</span> <span class="hljs-keyword">TABLE</span> t ( a <span class="hljs-type">INT</span>, b <span class="hljs-type">INT</span> <span class="hljs-keyword">PARTITION</span> <span class="hljs-keyword">BY</span> LIST (a) ( <span class="hljs-keyword">PARTITION</span> p0 <span class="hljs-keyword">VALUES</span> <span class="hljs-keyword">IN</span> (<span class="hljs-number">1</span>, <span class="hljs-number">2</span>, <span class="hljs-number">3</span>), <span class="hljs-keyword">PARTITION</span> p1 <span class="hljs-keyword">VALUES</span> <span class="hljs-keyword">IN</span> (<span class="hljs-number">4</span>, <span class="hljs-number">5</span>, <span class="hljs-number">6</span>) Query OK, <span class="hljs-number">0</span> <span class="hljs-keyword">rows</span> affected (<span class="hljs-number">0.11</span> sec) </div><button class="MuiButtonBase-root MuiIconButton-root MuiIconButton-sizeSmall css-1rmx1rm" tabindex="0" type="button" aria-label="Toggle code wrap"><svg class="MuiSvgIcon-root MuiSvgIcon-fontSizeInherit css-1cw4hi4" focusable="false" aria-hidden="true" viewbox="0 0 24 24" data-testid="WrapTextIcon"><path d="M4 19h6v-2H4v2zM20 5H4v2h16V5zm-3 6H4v2h13.25c1.1 0 2 .9 2 2s-.9 2-2 2H15v-2l-3 3 3 3v-2h2c2.21 0 4-1.79 4-4s-1.79-4-4-4z"/></svg></button><button class="MuiButtonBase-root MuiIconButton-root MuiIconButton-sizeSmall css-fxo539" tabindex="0" type="button" aria-label="copy"><svg class="MuiSvgIcon-root MuiSvgIcon-fontSizeInherit css-1cw4hi4" focusable="false" aria-hidden="true" viewbox="0 0 24 24" data-testid="ContentCopyIcon"><path d="M16 1H4c-1.1 0-2 .9-2 2v14h2V3h12V1zm3 4H8c-1.1 0-2 .9-2 2v14c0 1.1.9 2 2 2h11c1.1 0 2-.9 2-2V7c0-1.1-.9-2-2-2zm0 16H8V7h11v14z"/></svg></button></code></pre><p>通过以下语句，你可以在该表中添加一个名为 <code>pDef</code> 的默认 List 分区：</p><pre><code class="hljs language-sql"><div class="MuiBox-root css-1qhimia"><span class="hljs-keyword">ALTER</span> <span class="hljs-keyword">TABLE</span> t <span class="hljs-keyword">ADD</span> <span class="hljs-keyword">PARTITION</span> (<span class="hljs-keyword">PARTITION</span> pDef <span class="hljs-keyword">DEFAULT</span>); </div><button class="MuiButtonBase-root MuiIconButton-root MuiIconButton-sizeSmall css-1rmx1rm" tabindex="0" type="button" aria-label="Toggle code wrap"><svg class="MuiSvgIcon-root MuiSvgIcon-fontSizeInherit css-1cw4hi4" focusable="false" aria-hidden="true" viewbox="0 0 24 24" data-testid="WrapTextIcon"><path d="M4 19h6v-2H4v2zM20 5H4v2h16V5zm-3 6H4v2h13.25c1.1 0 2 .9 2 2s-.9 2-2 2H15v-2l-3 3 3 3v-2h2c2.21 0 4-1.79 4-4s-1.79-4-4-4z"/></svg></button><button class="MuiButtonBase-root MuiIconButton-root MuiIconButton-sizeSmall css-fxo539" tabindex="0" type="button" aria-label="copy"><svg class="MuiSvgIcon-root MuiSvgIcon-fontSizeInherit css-1cw4hi4" focusable="false" aria-hidden="true" viewbox="0 0 24 24" data-testid="ContentCopyIcon"><path d="M16 1H4c-1.1 0-2 .9-2 2v14h2V3h12V1zm3 4H8c-1.1 0-2 .9-2 2v14c0 1.1.9 2 2 2h11c1.1 0 2-.9 2-2V7c0-1.1-.9-2-2-2zm0 16H8V7h11v14z"/></svg></button></code></pre><p>或者</p><pre><code class="hljs language-sql"><div class="MuiBox-root css-1qhimia"><span class="hljs-keyword">ALTER</span> <span class="hljs-keyword">TABLE</span> t <span class="hljs-keyword">ADD</span> <span class="hljs-keyword">PARTITION</span> (<span class="hljs-keyword">PARTITION</span> pDef <span class="hljs-keyword">VALUES</span> <span class="hljs-keyword">IN</span> (<span class="hljs-keyword">DEFAULT</span>)); </div><button class="MuiButtonBase-root MuiIconButton-root MuiIconButton-sizeSmall css-1rmx1rm" tabindex="0" type="button" aria-label="Toggle code wrap"><svg class="MuiSvgIcon-root MuiSvgIcon-fontSizeInherit css-1cw4hi4" focusable="false" aria-hidden="true" viewbox="0 0 24 24" data-testid="WrapTextIcon"><path d="M4 19h6v-2H4v2zM20 5H4v2h16V5zm-3 6H4v2h13.25c1.1 0 2 .9 2 2s-.9 2-2 2H15v-2l-3 3 3 3v-2h2c2.21 0 4-1.79 4-4s-1.79-4-4-4z"/></svg></button><button class="MuiButtonBase-root MuiIconButton-root MuiIconButton-sizeSmall css-fxo539" tabindex="0" type="button" aria-label="copy"><svg class="MuiSvgIcon-root MuiSvgIcon-fontSizeInherit css-1cw4hi4" focusable="false" aria-hidden="true" viewbox="0 0 24 24" data-testid="ContentCopyIcon"><path d="M16 1H4c-1.1 0-2 .9-2 2v14h2V3h12V1zm3 4H8c-1.1 0-2 .9-2 2v14c0 1.1.9 2 2 2h11c1.1 0 2-.9 2-2V7c0-1.1-.9-2-2-2zm0 16H8V7h11v14z"/></svg></button></code></pre><p>此时，如果新插入该表中的值不匹配任何分区的数据集合，对应的数据会自动写入默认分区。</p><pre><code class="hljs language-sql"><div class="MuiBox-root css-1qhimia"><span class="hljs-keyword">INSERT</span> <span class="hljs-keyword">INTO</span> t <span class="hljs-keyword">VALUES</span> (<span class="hljs-number">7</span>, <span class="hljs-number">7</span>); Query OK, <span class="hljs-number">1</span> <span class="hljs-type">row</span> affected (<span class="hljs-number">0.01</span> sec) </div><button class="MuiButtonBase-root MuiIconButton-root MuiIconButton-sizeSmall css-1rmx1rm" tabindex="0" type="button" aria-label="Toggle code wrap"><svg class="MuiSvgIcon-root MuiSvgIcon-fontSizeInherit css-1cw4hi4" focusable="false" aria-hidden="true" viewbox="0 0 24 24" data-testid="WrapTextIcon"><path d="M4 19h6v-2H4v2zM20 5H4v2h16V5zm-3 6H4v2h13.25c1.1 0 2 .9 2 2s-.9 2-2 2H15v-2l-3 3 3 3v-2h2c2.21 0 4-1.79 4-4s-1.79-4-4-4z"/></svg></button><button class="MuiButtonBase-root MuiIconButton-root MuiIconButton-sizeSmall css-fxo539" tabindex="0" type="button" aria-label="copy"><svg class="MuiSvgIcon-root MuiSvgIcon-fontSizeInherit css-1cw4hi4" focusable="false" aria-hidden="true" viewbox="0 0 24 24" data-testid="ContentCopyIcon"><path d="M16 1H4c-1.1 0-2 .9-2 2v14h2V3h12V1zm3 4H8c-1.1 0-2 .9-2 2v14c0 1.1.9 2 2 2h11c1.1 0 2-.9 2-2V7c0-1.1-.9-2-2-2zm0 16H8V7h11v14z"/></svg></button></code></pre><p>你也可以在创建 List 或 List COLUMNS 分区表时添加默认分区。例如：</p><pre><code class="hljs language-sql"><div class="MuiBox-root css-1qhimia"><span class="hljs-keyword">CREATE</span> <span class="hljs-keyword">TABLE</span> employees ( id <span class="hljs-type">INT</span> <span class="hljs-keyword">NOT</span> <span class="hljs-keyword">NULL</span>, hired <span class="hljs-type">DATE</span> <span class="hljs-keyword">NOT</span> <span class="hljs-keyword">NULL</span> <span class="hljs-keyword">DEFAULT</span> <span class="hljs-string">'1970-01-01'</span>, store_id <span class="hljs-type">INT</span> <span class="hljs-keyword">PARTITION</span> <span class="hljs-keyword">BY</span> LIST (store_id) ( <span class="hljs-keyword">PARTITION</span> pNorth <span class="hljs-keyword">VALUES</span> <span class="hljs-keyword">IN</span> (<span class="hljs-number">1</span>, <span class="hljs-number">2</span>, <span class="hljs-number">3</span>, <span class="hljs-number">4</span>, <span class="hljs-number">5</span>), <span class="hljs-keyword">PARTITION</span> pEast <span class="hljs-keyword">VALUES</span> <span class="hljs-keyword">IN</span> (<span class="hljs-number">6</span>, <span class="hljs-number">7</span>, <span class="hljs-number">8</span>, <span class="hljs-number">9</span>, <span class="hljs-number">10</span>), <span class="hljs-keyword">PARTITION</span> pWest <span class="hljs-keyword">VALUES</span> <span class="hljs-keyword">IN</span> (<span class="hljs-number">11</span>, <span class="hljs-number">12</span>, <span class="hljs-number">13</span>, <span class="hljs-number">14</span>, <span class="hljs-number">15</span>), <span class="hljs-keyword">PARTITION</span> pCentral <span class="hljs-keyword">VALUES</span> <span class="hljs-keyword">IN</span> (<span class="hljs-number">16</span>, <span class="hljs-number">17</span>, <span class="hljs-number">18</span>, <span class="hljs-number">19</span>, <span class="hljs-number">20</span>), <span class="hljs-keyword">PARTITION</span> pDefault <span class="hljs-keyword">DEFAULT</span> </div><button class="MuiButtonBase-root MuiIconButton-root MuiIconButton-sizeSmall css-1rmx1rm" tabindex="0" type="button" aria-label="Toggle code wrap"><svg class="MuiSvgIcon-root MuiSvgIcon-fontSizeInherit css-1cw4hi4" focusable="false" aria-hidden="true" viewbox="0 0 24 24" data-testid="WrapTextIcon"><path d="M4 19h6v-2H4v2zM20 5H4v2h16V5zm-3 6H4v2h13.25c1.1 0 2 .9 2 2s-.9 2-2 2H15v-2l-3 3 3 3v-2h2c2.21 0 4-1.79 4-4s-1.79-4-4-4z"/></svg></button><button class="MuiButtonBase-root MuiIconButton-root MuiIconButton-sizeSmall css-fxo539" tabindex="0" type="button" aria-label="copy"><svg class="MuiSvgIcon-root MuiSvgIcon-fontSizeInherit css-1cw4hi4" focusable="false" aria-hidden="true" viewbox="0 0 24 24" data-testid="ContentCopyIcon"><path d="M16 1H4c-1.1 0-2 .9-2 2v14h2V3h12V1zm3 4H8c-1.1 0-2 .9-2 2v14c0 1.1.9 2 2 2h11c1.1 0 2-.9 2-2V7c0-1.1-.9-2-2-2zm0 16H8V7h11v14z"/></svg></button></code></pre><p>对于不包含默认分区的 List 或 List COLUMNS 分区表，<code>INSERT</code> 语句要插入的值需要匹配该表 <code>PARTITION ... VALUES IN (...)</code> 子句中定义的数据集合。如果要插入的值不匹配任何分区的数据集合，该语句将执行失败并报错，如下例所示：</p><pre><code class="hljs language-sql"><div class="MuiBox-root css-1qhimia"><span class="hljs-keyword">CREATE</span> <span class="hljs-keyword">TABLE</span> t ( a <span class="hljs-type">INT</span>, b <span class="hljs-type">INT</span> <span class="hljs-keyword">PARTITION</span> <span class="hljs-keyword">BY</span> LIST (a) ( <span class="hljs-keyword">PARTITION</span> p0 <span class="hljs-keyword">VALUES</span> <span class="hljs-keyword">IN</span> (<span class="hljs-number">1</span>, <span class="hljs-number">2</span>, <span class="hljs-number">3</span>), <span class="hljs-keyword">PARTITION</span> p1 <span class="hljs-keyword">VALUES</span> <span class="hljs-keyword">IN</span> (<span class="hljs-number">4</span>, <span class="hljs-number">5</span>, <span class="hljs-number">6</span>) Query OK, <span class="hljs-number">0</span> <span class="hljs-keyword">rows</span> affected (<span class="hljs-number">0.11</span> sec) <span class="hljs-keyword">INSERT</span> <span class="hljs-keyword">INTO</span> t <span class="hljs-keyword">VALUES</span> (<span class="hljs-number">7</span>, <span class="hljs-number">7</span>); ERROR <span class="hljs-number">1525</span> (HY000): <span class="hljs-keyword">Table</span> has <span class="hljs-keyword">no</span> <span class="hljs-keyword">partition</span> <span class="hljs-keyword">for</span> <span class="hljs-keyword">value</span> <span class="hljs-number">7</span> </div><button class="MuiButtonBase-root MuiIconButton-root MuiIconButton-sizeSmall css-1rmx1rm" tabindex="0" type="button" aria-label="Toggle code wrap"><svg class="MuiSvgIcon-root MuiSvgIcon-fontSizeInherit css-1cw4hi4" focusable="false" aria-hidden="true" viewbox="0 0 24 24" data-testid="WrapTextIcon"><path d="M4 19h6v-2H4v2zM20 5H4v2h16V5zm-3 6H4v2h13.25c1.1 0 2 .9 2 2s-.9 2-2 2H15v-2l-3 3 3 3v-2h2c2.21 0 4-1.79 4-4s-1.79-4-4-4z"/></svg></button><button class="MuiButtonBase-root MuiIconButton-root MuiIconButton-sizeSmall css-fxo539" tabindex="0" type="button" aria-label="copy"><svg class="MuiSvgIcon-root MuiSvgIcon-fontSizeInherit css-1cw4hi4" focusable="false" aria-hidden="true" viewbox="0 0 24 24" data-testid="ContentCopyIcon"><path d="M16 1H4c-1.1 0-2 .9-2 2v14h2V3h12V1zm3 4H8c-1.1 0-2 .9-2 2v14c0 1.1.9 2 2 2h11c1.1 0 2-.9 2-2V7c0-1.1-.9-2-2-2zm0 16H8V7h11v14z"/></svg></button></code></pre><p>要忽略以上错误，可以在 <code>INSERT</code> 语句中添加 <code>IGNORE</code> 关键字。添加该关键字后，<code>INSERT</code> 语句只会插入那些匹配分区数据集合的行，不会插入不匹配的行，并且不会报错：</p><pre><code class="hljs language-sql"><div class="MuiBox-root css-1qhimia">test<span class="hljs-operator">&gt;</span> <span class="hljs-keyword">TRUNCATE</span> t; Query OK, <span class="hljs-number">1</span> <span class="hljs-type">row</span> affected (<span class="hljs-number">0.00</span> sec) test<span class="hljs-operator">&gt;</span> <span class="hljs-keyword">INSERT</span> IGNORE <span class="hljs-keyword">INTO</span> t <span class="hljs-keyword">VALUES</span> (<span class="hljs-number">1</span>, <span class="hljs-number">1</span>), (<span class="hljs-number">7</span>, <span class="hljs-number">7</span>), (<span class="hljs-number">8</span>, <span class="hljs-number">8</span>), (<span class="hljs-number">3</span>, <span class="hljs-number">3</span>), (<span class="hljs-number">5</span>, <span class="hljs-number">5</span>); Query OK, <span class="hljs-number">3</span> <span class="hljs-keyword">rows</span> affected, <span class="hljs-number">2</span> warnings (<span class="hljs-number">0.01</span> sec) Records: <span class="hljs-number">5</span> Duplicates: <span class="hljs-number">2</span> Warnings: <span class="hljs-number">2</span> test<span class="hljs-operator">&gt;</span> <span class="hljs-keyword">select</span> <span class="hljs-operator">*</span> <span class="hljs-keyword">from</span> t; <span class="hljs-operator">+</span><span class="hljs-comment">------+------+</span> <span class="hljs-operator">|</span> a <span class="hljs-operator">|</span> b <span class="hljs-operator">|</span> <span class="hljs-operator">+</span><span class="hljs-comment">------+------+</span> <span class="hljs-operator">|</span> <span class="hljs-number">5</span> <span class="hljs-operator">|</span> <span class="hljs-number">5</span> <span class="hljs-operator">|</span> <span class="hljs-operator">|</span> <span class="hljs-number">1</span> <span class="hljs-operator">|</span> <span class="hljs-number">1</span> <span class="hljs-operator">|</span> <span class="hljs-operator">|</span> <span class="hljs-number">3</span> <span class="hljs-operator">|</span> <span class="hljs-number">3</span> <span class="hljs-operator">|</span> <span class="hljs-operator">+</span><span class="hljs-comment">------+------+</span> <span class="hljs-number">3</span> <span class="hljs-keyword">rows</span> <span class="hljs-keyword">in</span> <span class="hljs-keyword">set</span> (<span class="hljs-number">0.01</span> sec) </div><button class="MuiButtonBase-root MuiIconButton-root MuiIconButton-sizeSmall css-1rmx1rm" tabindex="0" type="button" aria-label="Toggle code wrap"><svg class="MuiSvgIcon-root MuiSvgIcon-fontSizeInherit css-1cw4hi4" focusable="false" aria-hidden="true" viewbox="0 0 24 24" data-testid="WrapTextIcon"><path d="M4 19h6v-2H4v2zM20 5H4v2h16V5zm-3 6H4v2h13.25c1.1 0 2 .9 2 2s-.9 2-2 2H15v-2l-3 3 3 3v-2h2c2.21 0 4-1.79 4-4s-1.79-4-4-4z"/></svg></button><button class="MuiButtonBase-root MuiIconButton-root MuiIconButton-sizeSmall css-fxo539" tabindex="0" type="button" aria-label="copy"><svg class="MuiSvgIcon-root MuiSvgIcon-fontSizeInherit css-1cw4hi4" focusable="false" aria-hidden="true" viewbox="0 0 24 24" data-testid="ContentCopyIcon"><path d="M16 1H4c-1.1 0-2 .9-2 2v14h2V3h12V1zm3 4H8c-1.1 0-2 .9-2 2v14c0 1.1.9 2 2 2h11c1.1 0 2-.9 2-2V7c0-1.1-.9-2-2-2zm0 16H8V7h11v14z"/></svg></button></code></pre><h3 id="list-columns-分区" style="position:relative"><a href="#list-columns-%E5%88%86%E5%8C%BA" aria-label="list columns 分区 permalink" class="anchor before"><svg aria-hidden="true" focusable="false" height="16" version="1.1" viewbox="0 0 16 16" width="16"><path fill-rule="evenodd" d="M4 9h1v1H4c-1.5 0-3-1.69-3-3.5S2.55 3 4 3h4c1.45 0 3 1.69 3 3.5 0 1.41-.91 2.72-2 3.25V8.59c.58-.45 1-1.27 1-2.09C10 5.22 8.98 4 8 4H4c-.98 0-2 1.22-2 2.5S3 9 4 9zm9-3h-1v1h1c1 0 2 1.22 2 2.5S13.98 12 13 12H9c-.98 0-2-1.22-2-2.5 0-.83.42-1.64 1-2.09V6.25c-1.09.53-2 1.84-2 3.25C6 11.31 7.55 13 9 13h4c1.45 0 3-1.69 3-3.5S14.5 6 13 6z"/></svg></a>List COLUMNS 分区</h3><p>List COLUMNS 分区是 List 分区的一种变体，可以将多个列用作分区键，并且可以将整数类型以外的数据类型的列用作分区列。你还可以使用字符串类型、<code>DATE</code> 和 <code>DATETIME</code> 类型的列。</p><p>假设商店员工分别来自以下 12 个城市，想要根据相关规定分成 4 个区域，如下表所示：</p><pre><code class="hljs language-"><div class="MuiBox-root css-1qhimia">| Region | Cities | | :----- | ------------------------------ | | 1 | LosAngeles,Seattle, Houston | | 2 | Chicago, Columbus, Boston | | 3 | NewYork, LongIsland, Baltimore | | 4 | Atlanta, Raleigh, Cincinnati | </div><button class="MuiButtonBase-root MuiIconButton-root MuiIconButton-sizeSmall css-1rmx1rm" tabindex="0" type="button" aria-label="Toggle code wrap"><svg class="MuiSvgIcon-root MuiSvgIcon-fontSizeInherit css-1cw4hi4" focusable="false" aria-hidden="true" viewbox="0 0 24 24" data-testid="WrapTextIcon"><path d="M4 19h6v-2H4v2zM20 5H4v2h16V5zm-3 6H4v2h13.25c1.1 0 2 .9 2 2s-.9 2-2 2H15v-2l-3 3 3 3v-2h2c2.21 0 4-1.79 4-4s-1.79-4-4-4z"/></svg></button><button class="MuiButtonBase-root MuiIconButton-root MuiIconButton-sizeSmall css-fxo539" tabindex="0" type="button" aria-label="copy"><svg class="MuiSvgIcon-root MuiSvgIcon-fontSizeInherit css-1cw4hi4" focusable="false" aria-hidden="true" viewbox="0 0 24 24" data-testid="ContentCopyIcon"><path d="M16 1H4c-1.1 0-2 .9-2 2v14h2V3h12V1zm3 4H8c-1.1 0-2 .9-2 2v14c0 1.1.9 2 2 2h11c1.1 0 2-.9 2-2V7c0-1.1-.9-2-2-2zm0 16H8V7h11v14z"/></svg></button></code></pre><p>使用列表列分区，你可以为员工数据创建一张表，将每行数据存储在员工所在城市对应的分区中，如下所示：</p><pre><code class="hljs language-sql"><div class="MuiBox-root css-1qhimia"><span class="hljs-keyword">CREATE</span> <span class="hljs-keyword">TABLE</span> employees_1 ( id <span class="hljs-type">INT</span> <span class="hljs-keyword">NOT</span> <span class="hljs-keyword">NULL</span>, fname <span class="hljs-type">VARCHAR</span>(<span class="hljs-number">30</span>), lname <span class="hljs-type">VARCHAR</span>(<span class="hljs-number">30</span>), hired <span class="hljs-type">DATE</span> <span class="hljs-keyword">NOT</span> <span class="hljs-keyword">NULL</span> <span class="hljs-keyword">DEFAULT</span> <span class="hljs-string">'1970-01-01'</span>, separated <span class="hljs-type">DATE</span> <span class="hljs-keyword">DEFAULT</span> <span class="hljs-string">'9999-12-31'</span>, job_code <span class="hljs-type">INT</span>, store_id <span class="hljs-type">INT</span>, city <span class="hljs-type">VARCHAR</span>(<span class="hljs-number">15</span>) <span class="hljs-keyword">PARTITION</span> <span class="hljs-keyword">BY</span> LIST COLUMNS(city) ( <span class="hljs-keyword">PARTITION</span> pRegion_1 <span class="hljs-keyword">VALUES</span> <span class="hljs-keyword">IN</span>(<span class="hljs-string">'LosAngeles'</span>, <span class="hljs-string">'Seattle'</span>, <span class="hljs-string">'Houston'</span>), <span class="hljs-keyword">PARTITION</span> pRegion_2 <span class="hljs-keyword">VALUES</span> <span class="hljs-keyword">IN</span>(<span class="hljs-string">'Chicago'</span>, <span class="hljs-string">'Columbus'</span>, <span class="hljs-string">'Boston'</span>), <span class="hljs-keyword">PARTITION</span> pRegion_3 <span class="hljs-keyword">VALUES</span> <span class="hljs-keyword">IN</span>(<span class="hljs-string">'NewYork'</span>, <span class="hljs-string">'LongIsland'</span>, <span class="hljs-string">'Baltimore'</span>), <span class="hljs-keyword">PARTITION</span> pRegion_4 <span class="hljs-keyword">VALUES</span> <span class="hljs-keyword">IN</span>(<span class="hljs-string">'Atlanta'</span>, <span class="hljs-string">'Raleigh'</span>, <span class="hljs-string">'Cincinnati'</span>) </div><button class="MuiButtonBase-root MuiIconButton-root MuiIconButton-sizeSmall css-1rmx1rm" tabindex="0" type="button" aria-label="Toggle code wrap"><svg class="MuiSvgIcon-root MuiSvgIcon-fontSizeInherit css-1cw4hi4" focusable="false" aria-hidden="true" viewbox="0 0 24 24" data-testid="WrapTextIcon"><path d="M4 19h6v-2H4v2zM20 5H4v2h16V5zm-3 6H4v2h13.25c1.1 0 2 .9 2 2s-.9 2-2 2H15v-2l-3 3 3 3v-2h2c2.21 0 4-1.79 4-4s-1.79-4-4-4z"/></svg></button><button class="MuiButtonBase-root MuiIconButton-root MuiIconButton-sizeSmall css-fxo539" tabindex="0" type="button" aria-label="copy"><svg class="MuiSvgIcon-root MuiSvgIcon-fontSizeInherit css-1cw4hi4" focusable="false" aria-hidden="true" viewbox="0 0 24 24" data-testid="ContentCopyIcon"><path d="M16 1H4c-1.1 0-2 .9-2 2v14h2V3h12V1zm3 4H8c-1.1 0-2 .9-2 2v14c0 1.1.9 2 2 2h11c1.1 0 2-.9 2-2V7c0-1.1-.9-2-2-2zm0 16H8V7h11v14z"/></svg></button></code></pre><p>与 List 分区不同的是，你不需要在 <code>COLUMNS()</code> 子句中使用表达式来将列值转换为整数。</p><p>List COLUMNS 分区也可以使用 <code>DATE</code> 和 <code>DATETIME</code> 类型的列进行分区，如以下示例中所示，该示例使用与先前的 <code>employees_1</code> 表相同的名称和列，但根据 <code>hired</code> 列采用 List COLUMNS 分区：</p><pre><code class="hljs language-sql"><div class="MuiBox-root css-1qhimia"><span class="hljs-keyword">CREATE</span> <span class="hljs-keyword">TABLE</span> employees_2 ( id <span class="hljs-type">INT</span> <span class="hljs-keyword">NOT</span> <span class="hljs-keyword">NULL</span>, fname <span class="hljs-type">VARCHAR</span>(<span class="hljs-number">30</span>), lname <span class="hljs-type">VARCHAR</span>(<span class="hljs-number">30</span>), hired <span class="hljs-type">DATE</span> <span class="hljs-keyword">NOT</span> <span class="hljs-keyword">NULL</span> <span class="hljs-keyword">DEFAULT</span> <span class="hljs-string">'1970-01-01'</span>, separated <span class="hljs-type">DATE</span> <span class="hljs-keyword">DEFAULT</span> <span class="hljs-string">'9999-12-31'</span>, job_code <span class="hljs-type">INT</span>, store_id <span class="hljs-type">INT</span>, city <span class="hljs-type">VARCHAR</span>(<span class="hljs-number">15</span>) <span class="hljs-keyword">PARTITION</span> <span class="hljs-keyword">BY</span> LIST COLUMNS(hired) ( <span class="hljs-keyword">PARTITION</span> pWeek_1 <span class="hljs-keyword">VALUES</span> <span class="hljs-keyword">IN</span>(<span class="hljs-string">'2020-02-01'</span>, <span class="hljs-string">'2020-02-02'</span>, <span class="hljs-string">'2020-02-03'</span>, <span class="hljs-string">'2020-02-04'</span>, <span class="hljs-string">'2020-02-05'</span>, <span class="hljs-string">'2020-02-06'</span>, <span class="hljs-string">'2020-02-07'</span>), <span class="hljs-keyword">PARTITION</span> pWeek_2 <span class="hljs-keyword">VALUES</span> <span class="hljs-keyword">IN</span>(<span class="hljs-string">'2020-02-08'</span>, <span class="hljs-string">'2020-02-09'</span>, <span class="hljs-string">'2020-02-10'</span>, <span class="hljs-string">'2020-02-11'</span>, <span class="hljs-string">'2020-02-12'</span>, <span class="hljs-string">'2020-02-13'</span>, <span class="hljs-string">'2020-02-14'</span>), <span class="hljs-keyword">PARTITION</span> pWeek_3 <span class="hljs-keyword">VALUES</span> <span class="hljs-keyword">IN</span>(<span class="hljs-string">'2020-02-15'</span>, <span class="hljs-string">'2020-02-16'</span>, <span class="hljs-string">'2020-02-17'</span>, <span class="hljs-string">'2020-02-18'</span>, <span class="hljs-string">'2020-02-19'</span>, <span class="hljs-string">'2020-02-20'</span>, <span class="hljs-string">'2020-02-21'</span>), <span class="hljs-keyword">PARTITION</span> pWeek_4 <span class="hljs-keyword">VALUES</span> <span class="hljs-keyword">IN</span>(<span class="hljs-string">'2020-02-22'</span>, <span class="hljs-string">'2020-02-23'</span>, <span class="hljs-string">'2020-02-24'</span>, <span class="hljs-string">'2020-02-25'</span>, <span class="hljs-string">'2020-02-26'</span>, <span class="hljs-string">'2020-02-27'</span>, <span class="hljs-string">'2020-02-28'</span>) </div><button class="MuiButtonBase-root MuiIconButton-root MuiIconButton-sizeSmall css-1rmx1rm" tabindex="0" type="button" aria-label="Toggle code wrap"><svg class="MuiSvgIcon-root MuiSvgIcon-fontSizeInherit css-1cw4hi4" focusable="false" aria-hidden="true" viewbox="0 0 24 24" data-testid="WrapTextIcon"><path d="M4 19h6v-2H4v2zM20 5H4v2h16V5zm-3 6H4v2h13.25c1.1 0 2 .9 2 2s-.9 2-2 2H15v-2l-3 3 3 3v-2h2c2.21 0 4-1.79 4-4s-1.79-4-4-4z"/></svg></button><button class="MuiButtonBase-root MuiIconButton-root MuiIconButton-sizeSmall css-fxo539" tabindex="0" type="button" aria-label="copy"><svg class="MuiSvgIcon-root MuiSvgIcon-fontSizeInherit css-1cw4hi4" focusable="false" aria-hidden="true" viewbox="0 0 24 24" data-testid="ContentCopyIcon"><path d="M16 1H4c-1.1 0-2 .9-2 2v14h2V3h12V1zm3 4H8c-1.1 0-2 .9-2 2v14c0 1.1.9 2 2 2h11c1.1 0 2-.9 2-2V7c0-1.1-.9-2-2-2zm0 16H8V7h11v14z"/></svg></button></code></pre><p>另外，你也可以在 <code>COLUMNS()</code> 子句中添加多个列，例如：</p><pre><code class="hljs language-sql"><div class="MuiBox-root css-1qhimia"><span class="hljs-keyword">CREATE</span> <span class="hljs-keyword">TABLE</span> t ( id <span class="hljs-type">int</span>, name <span class="hljs-type">varchar</span>(<span class="hljs-number">10</span>) <span class="hljs-keyword">PARTITION</span> <span class="hljs-keyword">BY</span> LIST COLUMNS(id,name) ( <span class="hljs-keyword">partition</span> p0 <span class="hljs-keyword">values</span> <span class="hljs-keyword">IN</span> ((<span class="hljs-number">1</span>,<span class="hljs-string">'a'</span>),(<span class="hljs-number">2</span>,<span class="hljs-string">'b'</span>)), <span class="hljs-keyword">partition</span> p1 <span class="hljs-keyword">values</span> <span class="hljs-keyword">IN</span> ((<span class="hljs-number">3</span>,<span class="hljs-string">'c'</span>),(<span class="hljs-number">4</span>,<span class="hljs-string">'d'</span>)), <span class="hljs-keyword">partition</span> p3 <span class="hljs-keyword">values</span> <span class="hljs-keyword">IN</span> ((<span class="hljs-number">5</span>,<span class="hljs-string">'e'</span>),(<span class="hljs-keyword">null</span>,<span class="hljs-keyword">null</span>)) </div><button class="MuiButtonBase-root MuiIconButton-root MuiIconButton-sizeSmall css-1rmx1rm" tabindex="0" type="button" aria-label="Toggle code wrap"><svg class="MuiSvgIcon-root MuiSvgIcon-fontSizeInherit css-1cw4hi4" focusable="false" aria-hidden="true" viewbox="0 0 24 24" data-testid="WrapTextIcon"><path d="M4 19h6v-2H4v2zM20 5H4v2h16V5zm-3 6H4v2h13.25c1.1 0 2 .9 2 2s-.9 2-2 2H15v-2l-3 3 3 3v-2h2c2.21 0 4-1.79 4-4s-1.79-4-4-4z"/></svg></button><button class="MuiButtonBase-root MuiIconButton-root MuiIconButton-sizeSmall css-fxo539" tabindex="0" type="button" aria-label="copy"><svg class="MuiSvgIcon-root MuiSvgIcon-fontSizeInherit css-1cw4hi4" focusable="false" aria-hidden="true" viewbox="0 0 24 24" data-testid="ContentCopyIcon"><path d="M16 1H4c-1.1 0-2 .9-2 2v14h2V3h12V1zm3 4H8c-1.1 0-2 .9-2 2v14c0 1.1.9 2 2 2h11c1.1 0 2-.9 2-2V7c0-1.1-.9-2-2-2zm0 16H8V7h11v14z"/></svg></button></code></pre><h3 id="hash-分区" style="position:relative"><a href="#hash-%E5%88%86%E5%8C%BA" aria-label="hash 分区 permalink" class="anchor before"><svg aria-hidden="true" focusable="false" height="16" version="1.1" viewbox="0 0 16 16" width="16"><path fill-rule="evenodd" d="M4 9h1v1H4c-1.5 0-3-1.69-3-3.5S2.55 3 4 3h4c1.45 0 3 1.69 3 3.5 0 1.41-.91 2.72-2 3.25V8.59c.58-.45 1-1.27 1-2.09C10 5.22 8.98 4 8 4H4c-.98 0-2 1.22-2 2.5S3 9 4 9zm9-3h-1v1h1c1 0 2 1.22 2 2.5S13.98 12 13 12H9c-.98 0-2-1.22-2-2.5 0-.83.42-1.64 1-2.09V6.25c-1.09.53-2 1.84-2 3.25C6 11.31 7.55 13 9 13h4c1.45 0 3-1.69 3-3.5S14.5 6 13 6z"/></svg></a>Hash 分区</h3><p>Hash 分区主要用于保证数据均匀地分散到一定数量的分区里面。在 Range 分区中你必须为每个分区指定值的范围；在 Hash 分区中，你只需要指定分区的数量。</p><p>创建 Hash 分区表时，需要在 <code>CREATE TABLE</code> 后面添加 <code>PARTITION BY HASH (expr)</code>，其中 <code>expr</code> 是一个返回整数的表达式。当这一列的类型是整数类型时，它可以是一个列名。此外，你很可能还需要加上 <code>PARTITIONS num</code>，其中 <code>num</code> 是一个正整数，表示将表划分多少分区。</p><p>下面的语句将创建一个 Hash 分区表，按 <code>store_id</code> 分成 4 个分区：</p><pre><code class="hljs language-sql"><div class="MuiBox-root css-1qhimia"><span class="hljs-keyword">CREATE</span> <span class="hljs-keyword">TABLE</span> employees ( id <span class="hljs-type">INT</span> <span class="hljs-keyword">NOT</span> <span class="hljs-keyword">NULL</span>, fname <span class="hljs-type">VARCHAR</span>(<span class="hljs-number">30</span>), lname <span class="hljs-type">VARCHAR</span>(<span class="hljs-number">30</span>), hired <span class="hljs-type">DATE</span> <span class="hljs-keyword">NOT</span> <span class="hljs-keyword">NULL</span> <span class="hljs-keyword">DEFAULT</span> <span class="hljs-string">'1970-01-01'</span>, separated <span class="hljs-type">DATE</span> <span class="hljs-keyword">DEFAULT</span> <span class="hljs-string">'9999-12-31'</span>, job_code <span class="hljs-type">INT</span>, store_id <span class="hljs-type">INT</span> <span class="hljs-keyword">PARTITION</span> <span class="hljs-keyword">BY</span> HASH(store_id) PARTITIONS <span class="hljs-number">4</span>; </div><button class="MuiButtonBase-root MuiIconButton-root MuiIconButton-sizeSmall css-1rmx1rm" tabindex="0" type="button" aria-label="Toggle code wrap"><svg class="MuiSvgIcon-root MuiSvgIcon-fontSizeInherit css-1cw4hi4" focusable="false" aria-hidden="true" viewbox="0 0 24 24" data-testid="WrapTextIcon"><path d="M4 19h6v-2H4v2zM20 5H4v2h16V5zm-3 6H4v2h13.25c1.1 0 2 .9 2 2s-.9 2-2 2H15v-2l-3 3 3 3v-2h2c2.21 0 4-1.79 4-4s-1.79-4-4-4z"/></svg></button><button class="MuiButtonBase-root MuiIconButton-root MuiIconButton-sizeSmall css-fxo539" tabindex="0" type="button" aria-label="copy"><svg class="MuiSvgIcon-root MuiSvgIcon-fontSizeInherit css-1cw4hi4" focusable="false" aria-hidden="true" viewbox="0 0 24 24" data-testid="ContentCopyIcon"><path d="M16 1H4c-1.1 0-2 .9-2 2v14h2V3h12V1zm3 4H8c-1.1 0-2 .9-2 2v14c0 1.1.9 2 2 2h11c1.1 0 2-.9 2-2V7c0-1.1-.9-2-2-2zm0 16H8V7h11v14z"/></svg></button></code></pre><p>如果不指定 <code>PARTITIONS num</code>，默认的分区数量为 1。</p><p>你也可以使用一个返回整数的 SQL 表达式。例如，你可以按入职年份分区：</p><pre><code class="hljs language-sql"><div class="MuiBox-root css-1qhimia"><span class="hljs-keyword">CREATE</span> <span class="hljs-keyword">TABLE</span> employees ( id <span class="hljs-type">INT</span> <span class="hljs-keyword">NOT</span> <span class="hljs-keyword">NULL</span>, fname <span class="hljs-type">VARCHAR</span>(<span class="hljs-number">30</span>), lname <span class="hljs-type">VARCHAR</span>(<span class="hljs-number">30</span>), hired <span class="hljs-type">DATE</span> <span class="hljs-keyword">NOT</span> <span class="hljs-keyword">NULL</span> <span class="hljs-keyword">DEFAULT</span> <span class="hljs-string">'1970-01-01'</span>, separated <span class="hljs-type">DATE</span> <span class="hljs-keyword">DEFAULT</span> <span class="hljs-string">'9999-12-31'</span>, job_code <span class="hljs-type">INT</span>, store_id <span class="hljs-type">INT</span> <span class="hljs-keyword">PARTITION</span> <span class="hljs-keyword">BY</span> HASH( <span class="hljs-keyword">YEAR</span>(hired) ) PARTITIONS <span class="hljs-number">4</span>; </div><button class="MuiButtonBase-root MuiIconButton-root MuiIconButton-sizeSmall css-1rmx1rm" tabindex="0" type="button" aria-label="Toggle code wrap"><svg class="MuiSvgIcon-root MuiSvgIcon-fontSizeInherit css-1cw4hi4" focusable="false" aria-hidden="true" viewbox="0 0 24 24" data-testid="WrapTextIcon"><path d="M4 19h6v-2H4v2zM20 5H4v2h16V5zm-3 6H4v2h13.25c1.1 0 2 .9 2 2s-.9 2-2 2H15v-2l-3 3 3 3v-2h2c2.21 0 4-1.79 4-4s-1.79-4-4-4z"/></svg></button><button class="MuiButtonBase-root MuiIconButton-root MuiIconButton-sizeSmall css-fxo539" tabindex="0" type="button" aria-label="copy"><svg class="MuiSvgIcon-root MuiSvgIcon-fontSizeInherit css-1cw4hi4" focusable="false" aria-hidden="true" viewbox="0 0 24 24" data-testid="ContentCopyIcon"><path d="M16 1H4c-1.1 0-2 .9-2 2v14h2V3h12V1zm3 4H8c-1.1 0-2 .9-2 2v14c0 1.1.9 2 2 2h11c1.1 0 2-.9 2-2V7c0-1.1-.9-2-2-2zm0 16H8V7h11v14z"/></svg></button></code></pre><p>最高效的 Hash 函数是作用在单列上，并且函数的单调性是跟列的值是一样递增或者递减的。</p><p>例如，<code>date_col</code> 是类型为 <code>DATE</code> 的列，表达式 <code>TO_DAYS(date_col)</code> 的值是直接随 <code>date_col</code> 的值变化的。<code>YEAR(date_col)</code> 跟 <code>TO_DAYS(date_col)</code> 就不太一样，因为不是每次 <code>date_col</code> 变化时 <code>YEAR(date_col)</code> 都会得到不同的值。</p><p>作为对比，假设我们有一个类型是 INT 的 <code>int_col</code> 的列。考虑一下表达式 <code>POW(5-int_col,3) + 6</code>，这并不是一个比较好的 Hash 函数，因为随着 <code>int_col</code> 的值的变化，表达式的结果不会成比例地变化。改变 <code>int_col</code> 的值会使表达式的结果的值变化巨大。例如，<code>int_col</code> 从 5 变到 6 表达式的结果变化是 -1，但是从 6 变到 7 的时候表达式的值的变化是 -7。</p><p>总而言之，表达式越接近 <code>y = cx</code> 的形式，它越是适合作为 Hash 函数。因为表达式越是非线性的，在各个分区上面的数据的分布越是倾向于不均匀。</p><p>理论上，Hash 分区也是可以做分区裁剪的。而实际上对于多列的情况，实现很难并且计算很耗时。因此，不推荐 Hash 分区在表达式中涉及多列。</p><p>使用 <code>PARTITIION BY HASH</code> 的时候，TiDB 通过表达式的结果做“取余”运算，决定数据落在哪个分区。换句话说，如果分区表达式是 <code>expr</code>，分区数是 <code>num</code>，则由 <code>MOD(expr, num)</code> 决定存储的分区。假设 <code>t1</code> 定义如下：</p><pre><code class="hljs language-sql"><div class="MuiBox-root css-1qhimia"><span class="hljs-keyword">CREATE</span> <span class="hljs-keyword">TABLE</span> t1 (col1 <span class="hljs-type">INT</span>, col2 <span class="hljs-type">CHAR</span>(<span class="hljs-number">5</span>), col3 <span class="hljs-type">DATE</span>) <span class="hljs-keyword">PARTITION</span> <span class="hljs-keyword">BY</span> HASH( <span class="hljs-keyword">YEAR</span>(col3) ) PARTITIONS <span class="hljs-number">4</span>; </div><button class="MuiButtonBase-root MuiIconButton-root MuiIconButton-sizeSmall css-1rmx1rm" tabindex="0" type="button" aria-label="Toggle code wrap"><svg class="MuiSvgIcon-root MuiSvgIcon-fontSizeInherit css-1cw4hi4" focusable="false" aria-hidden="true" viewbox="0 0 24 24" data-testid="WrapTextIcon"><path d="M4 19h6v-2H4v2zM20 5H4v2h16V5zm-3 6H4v2h13.25c1.1 0 2 .9 2 2s-.9 2-2 2H15v-2l-3 3 3 3v-2h2c2.21 0 4-1.79 4-4s-1.79-4-4-4z"/></svg></button><button class="MuiButtonBase-root MuiIconButton-root MuiIconButton-sizeSmall css-fxo539" tabindex="0" type="button" aria-label="copy"><svg class="MuiSvgIcon-root MuiSvgIcon-fontSizeInherit css-1cw4hi4" focusable="false" aria-hidden="true" viewbox="0 0 24 24" data-testid="ContentCopyIcon"><path d="M16 1H4c-1.1 0-2 .9-2 2v14h2V3h12V1zm3 4H8c-1.1 0-2 .9-2 2v14c0 1.1.9 2 2 2h11c1.1 0 2-.9 2-2V7c0-1.1-.9-2-2-2zm0 16H8V7h11v14z"/></svg></button></code></pre><p>向 <code>t1</code> 插入一行数据，其中 <code>col3</code> 列的值是 '2005-09-15'，这条数据会被插入到分区 1 中：</p><pre><code class="hljs language-"><div class="MuiBox-root css-1qhimia">MOD(YEAR('2005-09-01'),4) = MOD(2005,4) </div><button class="MuiButtonBase-root MuiIconButton-root MuiIconButton-sizeSmall css-1rmx1rm" tabindex="0" type="button" aria-label="Toggle code wrap"><svg class="MuiSvgIcon-root MuiSvgIcon-fontSizeInherit css-1cw4hi4" focusable="false" aria-hidden="true" viewbox="0 0 24 24" data-testid="WrapTextIcon"><path d="M4 19h6v-2H4v2zM20 5H4v2h16V5zm-3 6H4v2h13.25c1.1 0 2 .9 2 2s-.9 2-2 2H15v-2l-3 3 3 3v-2h2c2.21 0 4-1.79 4-4s-1.79-4-4-4z"/></svg></button><button class="MuiButtonBase-root MuiIconButton-root MuiIconButton-sizeSmall css-fxo539" tabindex="0" type="button" aria-label="copy"><svg class="MuiSvgIcon-root MuiSvgIcon-fontSizeInherit css-1cw4hi4" focusable="false" aria-hidden="true" viewbox="0 0 24 24" data-testid="ContentCopyIcon"><path d="M16 1H4c-1.1 0-2 .9-2 2v14h2V3h12V1zm3 4H8c-1.1 0-2 .9-2 2v14c0 1.1.9 2 2 2h11c1.1 0 2-.9 2-2V7c0-1.1-.9-2-2-2zm0 16H8V7h11v14z"/></svg></button></code></pre><h3 id="key-分区" style="position:relative"><a href="#key-%E5%88%86%E5%8C%BA" aria-label="key 分区 permalink" class="anchor before"><svg aria-hidden="true" focusable="false" height="16" version="1.1" viewbox="0 0 16 16" width="16"><path fill-rule="evenodd" d="M4 9h1v1H4c-1.5 0-3-1.69-3-3.5S2.55 3 4 3h4c1.45 0 3 1.69 3 3.5 0 1.41-.91 2.72-2 3.25V8.59c.58-.45 1-1.27 1-2.09C10 5.22 8.98 4 8 4H4c-.98 0-2 1.22-2 2.5S3 9 4 9zm9-3h-1v1h1c1 0 2 1.22 2 2.5S13.98 12 13 12H9c-.98 0-2-1.22-2-2.5 0-.83.42-1.64 1-2.09V6.25c-1.09.53-2 1.84-2 3.25C6 11.31 7.55 13 9 13h4c1.45 0 3-1.69 3-3.5S14.5 6 13 6z"/></svg></a>Key 分区</h3><p>TiDB 从 v7.0.0 开始支持 Key 分区。在 v7.0.0 之前的版本中，创建 Key 分区表时，TiDB 会将其创建为非分区表并给出告警。</p><p>Key 分区与 Hash 分区都可以保证将数据均匀地分散到一定数量的分区里面，区别是 Hash 分区只能根据一个指定的整数表达式或字段进行分区，而 Key 分区可以根据字段列表进行分区，且 Key 分区的分区字段不局限于整数类型。TiDB Key 分区表的 Hash 算法与 MySQL 不一样，因此表的数据分布也不一样。</p><p>创建 Key 分区表时，你需要在 <code>CREATE TABLE</code> 后面添加 <code>PARTITION BY KEY (columList)</code>，其中 <code>columnList</code> 是字段列表，可以包含一个或多个字段。每个字段的类型可以是除 <code>BLOB</code>、<code>JSON</code>、<code>GEOMETRY</code> 之外的任意类型（请注意 TiDB 不支持 <code>GEOMETRY</code> 类型）。此外，你很可能还需要加上 <code>PARTITIONS num</code>，其中 <code>num</code> 是一个正整数，表示将表划分多少个分区；或者加上分区名的定义，例如，加上 <code>(PARTITION p0, PARTITION p1)</code> 代表将表划分为两个分区，分区名为 <code>p0</code> 和 <code>p1</code>。</p><p>下面的语句将创建一个 Key 分区表，按 <code>store_id</code> 分成 4 个分区：</p><pre><code class="hljs language-sql"><div class="MuiBox-root css-1qhimia"><span class="hljs-keyword">CREATE</span> <span class="hljs-keyword">TABLE</span> employees ( id <span class="hljs-type">INT</span> <span class="hljs-keyword">NOT</span> <span class="hljs-keyword">NULL</span>, fname <span class="hljs-type">VARCHAR</span>(<span class="hljs-number">30</span>), lname <span class="hljs-type">VARCHAR</span>(<span class="hljs-number">30</span>), hired <span class="hljs-type">DATE</span> <span class="hljs-keyword">NOT</span> <span class="hljs-keyword">NULL</span> <span class="hljs-keyword">DEFAULT</span> <span class="hljs-string">'1970-01-01'</span>, separated <span class="hljs-type">DATE</span> <span class="hljs-keyword">DEFAULT</span> <span class="hljs-string">'9999-12-31'</span>, job_code <span class="hljs-type">INT</span>, store_id <span class="hljs-type">INT</span> <span class="hljs-keyword">PARTITION</span> <span class="hljs-keyword">BY</span> KEY(store_id) PARTITIONS <span class="hljs-number">4</span>; </div><button class="MuiButtonBase-root MuiIconButton-root MuiIconButton-sizeSmall css-1rmx1rm" tabindex="0" type="button" aria-label="Toggle code wrap"><svg class="MuiSvgIcon-root MuiSvgIcon-fontSizeInherit css-1cw4hi4" focusable="false" aria-hidden="true" viewbox="0 0 24 24" data-testid="WrapTextIcon"><path d="M4 19h6v-2H4v2zM20 5H4v2h16V5zm-3 6H4v2h13.25c1.1 0 2 .9 2 2s-.9 2-2 2H15v-2l-3 3 3 3v-2h2c2.21 0 4-1.79 4-4s-1.79-4-4-4z"/></svg></button><button class="MuiButtonBase-root MuiIconButton-root MuiIconButton-sizeSmall css-fxo539" tabindex="0" type="button" aria-label="copy"><svg class="MuiSvgIcon-root MuiSvgIcon-fontSizeInherit css-1cw4hi4" focusable="false" aria-hidden="true" viewbox="0 0 24 24" data-testid="ContentCopyIcon"><path d="M16 1H4c-1.1 0-2 .9-2 2v14h2V3h12V1zm3 4H8c-1.1 0-2 .9-2 2v14c0 1.1.9 2 2 2h11c1.1 0 2-.9 2-2V7c0-1.1-.9-2-2-2zm0 16H8V7h11v14z"/></svg></button></code></pre><p>如果不指定 <code>PARTITIONS num</code>，默认的分区数量为 1。</p><p>你也可以根据 VARCHAR 等非整数字段创建 Key 分区表。下面的语句按 <code>fname</code> 将表分成 4 个分区：</p><pre><code class="hljs language-sql"><div class="MuiBox-root css-1qhimia"><span class="hljs-keyword">CREATE</span> <span class="hljs-keyword">TABLE</span> employees ( id <span class="hljs-type">INT</span> <span class="hljs-keyword">NOT</span> <span class="hljs-keyword">NULL</span>, fname <span class="hljs-type">VARCHAR</span>(<span class="hljs-number">30</span>), lname <span class="hljs-type">VARCHAR</span>(<span class="hljs-number">30</span>), hired <span class="hljs-type">DATE</span> <span class="hljs-keyword">NOT</span> <span class="hljs-keyword">NULL</span> <span class="hljs-keyword">DEFAULT</span> <span class="hljs-string">'1970-01-01'</span>, separated <span class="hljs-type">DATE</span> <span class="hljs-keyword">DEFAULT</span> <span class="hljs-string">'9999-12-31'</span>, job_code <span class="hljs-type">INT</span>, store_id <span class="hljs-type">INT</span> <span class="hljs-keyword">PARTITION</span> <span class="hljs-keyword">BY</span> KEY(fname) PARTITIONS <span class="hljs-number">4</span>; </div><button class="MuiButtonBase-root MuiIconButton-root MuiIconButton-sizeSmall css-1rmx1rm" tabindex="0" type="button" aria-label="Toggle code wrap"><svg class="MuiSvgIcon-root MuiSvgIcon-fontSizeInherit css-1cw4hi4" focusable="false" aria-hidden="true" viewbox="0 0 24 24" data-testid="WrapTextIcon"><path d="M4 19h6v-2H4v2zM20 5H4v2h16V5zm-3 6H4v2h13.25c1.1 0 2 .9 2 2s-.9 2-2 2H15v-2l-3 3 3 3v-2h2c2.21 0 4-1.79 4-4s-1.79-4-4-4z"/></svg></button><button class="MuiButtonBase-root MuiIconButton-root MuiIconButton-sizeSmall css-fxo539" tabindex="0" type="button" aria-label="copy"><svg class="MuiSvgIcon-root MuiSvgIcon-fontSizeInherit css-1cw4hi4" focusable="false" aria-hidden="true" viewbox="0 0 24 24" data-testid="ContentCopyIcon"><path d="M16 1H4c-1.1 0-2 .9-2 2v14h2V3h12V1zm3 4H8c-1.1 0-2 .9-2 2v14c0 1.1.9 2 2 2h11c1.1 0 2-.9 2-2V7c0-1.1-.9-2-2-2zm0 16H8V7h11v14z"/></svg></button></code></pre><p>你还可以根据多列字段创建 Key 分区表。下面的语句按 <code>fname</code>、<code>store_id</code> 将表分成 4 个分区：</p><pre><code class="hljs language-sql"><div class="MuiBox-root css-1qhimia"><span class="hljs-keyword">CREATE</span> <span class="hljs-keyword">TABLE</span> employees ( id <span class="hljs-type">INT</span> <span class="hljs-keyword">NOT</span> <span class="hljs-keyword">NULL</span>, fname <span class="hljs-type">VARCHAR</span>(<span class="hljs-number">30</span>), lname <span class="hljs-type">VARCHAR</span>(<span class="hljs-number">30</span>), hired <span class="hljs-type">DATE</span> <span class="hljs-keyword">NOT</span> <span class="hljs-keyword">NULL</span> <span class="hljs-keyword">DEFAULT</span> <span class="hljs-string">'1970-01-01'</span>, separated <span class="hljs-type">DATE</span> <span class="hljs-keyword">DEFAULT</span> <span class="hljs-string">'9999-12-31'</span>, job_code <span class="hljs-type">INT</span>, store_id <span class="hljs-type">INT</span> <span class="hljs-keyword">PARTITION</span> <span class="hljs-keyword">BY</span> KEY(fname, store_id) PARTITIONS <span class="hljs-number">4</span>; </div><button class="MuiButtonBase-root MuiIconButton-root MuiIconButton-sizeSmall css-1rmx1rm" tabindex="0" type="button" aria-label="Toggle code wrap"><svg class="MuiSvgIcon-root MuiSvgIcon-fontSizeInherit css-1cw4hi4" focusable="false" aria-hidden="true" viewbox="0 0 24 24" data-testid="WrapTextIcon"><path d="M4 19h6v-2H4v2zM20 5H4v2h16V5zm-3 6H4v2h13.25c1.1 0 2 .9 2 2s-.9 2-2 2H15v-2l-3 3 3 3v-2h2c2.21 0 4-1.79 4-4s-1.79-4-4-4z"/></svg></button><button class="MuiButtonBase-root MuiIconButton-root MuiIconButton-sizeSmall css-fxo539" tabindex="0" type="button" aria-label="copy"><svg class="MuiSvgIcon-root MuiSvgIcon-fontSizeInherit css-1cw4hi4" focusable="false" aria-hidden="true" viewbox="0 0 24 24" data-testid="ContentCopyIcon"><path d="M16 1H4c-1.1 0-2 .9-2 2v14h2V3h12V1zm3 4H8c-1.1 0-2 .9-2 2v14c0 1.1.9 2 2 2h11c1.1 0 2-.9 2-2V7c0-1.1-.9-2-2-2zm0 16H8V7h11v14z"/></svg></button></code></pre><p>目前，TiDB 不支持分区字段列表 <code>PARTITION BY KEY</code> 为空的 Key 分区表。下面的语句将创建一个非分区表，并向客户端返回 <code>Unsupported partition type KEY, treat as normal table</code> 警告。</p><pre><code class="hljs language-sql"><div class="MuiBox-root css-1qhimia"><span class="hljs-keyword">CREATE</span> <span class="hljs-keyword">TABLE</span> employees ( id <span class="hljs-type">INT</span> <span class="hljs-keyword">NOT</span> <span class="hljs-keyword">NULL</span>, fname <span class="hljs-type">VARCHAR</span>(<span class="hljs-number">30</span>), lname <span class="hljs-type">VARCHAR</span>(<span class="hljs-number">30</span>), hired <span class="hljs-type">DATE</span> <span class="hljs-keyword">NOT</span> <span class="hljs-keyword">NULL</span> <span class="hljs-keyword">DEFAULT</span> <span class="hljs-string">'1970-01-01'</span>, separated <span class="hljs-type">DATE</span> <span class="hljs-keyword">DEFAULT</span> <span class="hljs-string">'9999-12-31'</span>, job_code <span class="hljs-type">INT</span>, store_id <span class="hljs-type">INT</span> <span class="hljs-keyword">PARTITION</span> <span class="hljs-keyword">BY</span> KEY() PARTITIONS <span class="hljs-number">4</span>; </div><button class="MuiButtonBase-root MuiIconButton-root MuiIconButton-sizeSmall css-1rmx1rm" tabindex="0" type="button" aria-label="Toggle code wrap"><svg class="MuiSvgIcon-root MuiSvgIcon-fontSizeInherit css-1cw4hi4" focusable="false" aria-hidden="true" viewbox="0 0 24 24" data-testid="WrapTextIcon"><path d="M4 19h6v-2H4v2zM20 5H4v2h16V5zm-3 6H4v2h13.25c1.1 0 2 .9 2 2s-.9 2-2 2H15v-2l-3 3 3 3v-2h2c2.21 0 4-1.79 4-4s-1.79-4-4-4z"/></svg></button><button class="MuiButtonBase-root MuiIconButton-root MuiIconButton-sizeSmall css-fxo539" tabindex="0" type="button" aria-label="copy"><svg class="MuiSvgIcon-root MuiSvgIcon-fontSizeInherit css-1cw4hi4" focusable="false" aria-hidden="true" viewbox="0 0 24 24" data-testid="ContentCopyIcon"><path d="M16 1H4c-1.1 0-2 .9-2 2v14h2V3h12V1zm3 4H8c-1.1 0-2 .9-2 2v14c0 1.1.9 2 2 2h11c1.1 0 2-.9 2-2V7c0-1.1-.9-2-2-2zm0 16H8V7h11v14z"/></svg></button></code></pre><h3 id="tidb-对-linear-hash-分区的处理" style="position:relative"><a href="#tidb-%E5%AF%B9-linear-hash-%E5%88%86%E5%8C%BA%E7%9A%84%E5%A4%84%E7%90%86" aria-label="tidb 对 linear hash 分区的处理 permalink" class="anchor before"><svg aria-hidden="true" focusable="false" height="16" version="1.1" viewbox="0 0 16 16" width="16"><path fill-rule="evenodd" d="M4 9h1v1H4c-1.5 0-3-1.69-3-3.5S2.55 3 4 3h4c1.45 0 3 1.69 3 3.5 0 1.41-.91 2.72-2 3.25V8.59c.58-.45 1-1.27 1-2.09C10 5.22 8.98 4 8 4H4c-.98 0-2 1.22-2 2.5S3 9 4 9zm9-3h-1v1h1c1 0 2 1.22 2 2.5S13.98 12 13 12H9c-.98 0-2-1.22-2-2.5 0-.83.42-1.64 1-2.09V6.25c-1.09.53-2 1.84-2 3.25C6 11.31 7.55 13 9 13h4c1.45 0 3-1.69 3-3.5S14.5 6 13 6z"/></svg></a>TiDB 对 Linear Hash 分区的处理</h3><p>在 v6.4.0 之前，如果在 TiDB 上执行 <a href="https://dev.mysql.com/doc/refman/8.0/en/partitioning-linear-hash.html" target="_blank" referrerpolicy="no-referrer-when-downgrade">MySQL Linear Hash 分区</a> 的 DDL 语句，TiDB 只能创建非分区表。在这种情况下，如果你仍然想要在 TiDB 中创建分区表，你需要修改这些 DDL 语句。</p><p>从 v6.4.0 起，TiDB 支持解析 MySQL 的 <code>PARTITION BY LINEAR HASH</code> 语法，但会忽略其中的 <code>LINEAR</code> 关键字。你可以直接在 TiDB 中执行现有的 MySQL Linear Hash 分区的 SQL 语句，而无需修改。</p><ul><li><p>对于 MySQL Linear Hash 分区的 <code>CREATE</code> 语句，TiDB 将创建一个常规的非线性 Hash 分区表（注意 TiDB 内部实际不存在 Linear Hash 分区表）。如果分区数是 2 的幂，该分区表中行的分布情况与 MySQL 相同。如果分区数不是 2 的幂，该分区表中行的分布情况与 MySQL 会有所差异。这是因为 TiDB 中非线性分区表使用简单的“分区模数”，而线性分区表使用“模数的下一个 2 次方并会折叠分区数和下一个 2 次方之间的值”。详情请见 <a href="https://github.com/pingcap/tidb/issues/38450" target="_blank" referrerpolicy="no-referrer-when-downgrade">#38450</a>。</p></li><li><p>对于 MySQL Linear Hash 分区的其他 SQL 语句，TiDB 将正常返回对应的 Hash 分区的查询结果。但当分区数不是 2 的幂（意味着分区表中行的分布情况与 MySQL 不同）时，<a href="#%E5%88%86%E5%8C%BA%E9%80%89%E6%8B%A9">分区选择</a>、<code>TRUNCATE PARTITION</code>、<code>EXCHANGE PARTITION</code> 返回的结果将和 MySQL 有所差异。</p></li></ul><h3 id="tidb-对-linear-key-分区的处理" style="position:relative"><a href="#tidb-%E5%AF%B9-linear-key-%E5%88%86%E5%8C%BA%E7%9A%84%E5%A4%84%E7%90%86" aria-label="tidb 对 linear key 分区的处理 permalink" class="anchor before"><svg aria-hidden="true" focusable="false" height="16" version="1.1" viewbox="0 0 16 16" width="16"><path fill-rule="evenodd" d="M4 9h1v1H4c-1.5 0-3-1.69-3-3.5S2.55 3 4 3h4c1.45 0 3 1.69 3 3.5 0 1.41-.91 2.72-2 3.25V8.59c.58-.45 1-1.27 1-2.09C10 5.22 8.98 4 8 4H4c-.98 0-2 1.22-2 2.5S3 9 4 9zm9-3h-1v1h1c1 0 2 1.22 2 2.5S13.98 12 13 12H9c-.98 0-2-1.22-2-2.5 0-.83.42-1.64 1-2.09V6.25c-1.09.53-2 1.84-2 3.25C6 11.31 7.55 13 9 13h4c1.45 0 3-1.69 3-3.5S14.5 6 13 6z"/></svg></a>TiDB 对 Linear Key 分区的处理</h3><p>TiDB 从 v7.0.0 开始支持 Key 分区，并支持解析 MySQL 的 <code>PARTITION BY LINEAR KEY</code> 语法，但会忽略其中的 <code>LINEAR</code> 关键字，只采用非线性 Hash 算法。</p><p>在 v7.0.0 之前的版本中，创建 Key 分区表时，TiDB 会将其创建为非分区表并给出告警。</p><h3 id="分区对-null-值的处理" style="position:relative"><a href="#%E5%88%86%E5%8C%BA%E5%AF%B9-null-%E5%80%BC%E7%9A%84%E5%A4%84%E7%90%86" aria-label="分区对 null 值的处理 permalink" class="anchor before"><svg aria-hidden="true" focusable="false" height="16" version="1.1" viewbox="0 0 16 16" width="16"><path fill-rule="evenodd" d="M4 9h1v1H4c-1.5 0-3-1.69-3-3.5S2.55 3 4 3h4c1.45 0 3 1.69 3 3.5 0 1.41-.91 2.72-2 3.25V8.59c.58-.45 1-1.27 1-2.09C10 5.22 8.98 4 8 4H4c-.98 0-2 1.22-2 2.5S3 9 4 9zm9-3h-1v1h1c1 0 2 1.22 2 2.5S13.98 12 13 12H9c-.98 0-2-1.22-2-2.5 0-.83.42-1.64 1-2.09V6.25c-1.09.53-2 1.84-2 3.25C6 11.31 7.55 13 9 13h4c1.45 0 3-1.69 3-3.5S14.5 6 13 6z"/></svg></a>分区对 NULL 值的处理</h3><p>TiDB 允许计算结果为 NULL 的分区表达式。注意，NULL 不是一个整数类型，NULL 小于所有的整数类型值，正如 <code>ORDER BY</code> 的规则一样。</p><h4 id="range-分区对-null-的处理" style="position:relative"><a href="#range-%E5%88%86%E5%8C%BA%E5%AF%B9-null-%E7%9A%84%E5%A4%84%E7%90%86" aria-label="range 分区对 null 的处理 permalink" class="anchor before"><svg aria-hidden="true" focusable="false" height="16" version="1.1" viewbox="0 0 16 16" width="16"><path fill-rule="evenodd" d="M4 9h1v1H4c-1.5 0-3-1.69-3-3.5S2.55 3 4 3h4c1.45 0 3 1.69 3 3.5 0 1.41-.91 2.72-2 3.25V8.59c.58-.45 1-1.27 1-2.09C10 5.22 8.98 4 8 4H4c-.98 0-2 1.22-2 2.5S3 9 4 9zm9-3h-1v1h1c1 0 2 1.22 2 2.5S13.98 12 13 12H9c-.98 0-2-1.22-2-2.5 0-.83.42-1.64 1-2.09V6.25c-1.09.53-2 1.84-2 3.25C6 11.31 7.55 13 9 13h4c1.45 0 3-1.69 3-3.5S14.5 6 13 6z"/></svg></a>Range 分区对 NULL 的处理</h4><p>如果插入一行到 Range 分区表，它的分区列的计算结果是 NULL，那么这一行会被插入到最小的那个分区。</p><pre><code class="hljs language-sql"><div class="MuiBox-root css-1qhimia"><span class="hljs-keyword">CREATE</span> <span class="hljs-keyword">TABLE</span> t1 ( c1 <span class="hljs-type">INT</span>, c2 <span class="hljs-type">VARCHAR</span>(<span class="hljs-number">20</span>) <span class="hljs-keyword">PARTITION</span> <span class="hljs-keyword">BY</span> <span class="hljs-keyword">RANGE</span>(c1) ( <span class="hljs-keyword">PARTITION</span> p0 <span class="hljs-keyword">VALUES</span> LESS THAN (<span class="hljs-number">0</span>), <span class="hljs-keyword">PARTITION</span> p1 <span class="hljs-keyword">VALUES</span> LESS THAN (<span class="hljs-number">10</span>), <span class="hljs-keyword">PARTITION</span> p2 <span class="hljs-keyword">VALUES</span> LESS THAN MAXVALUE </div><button class="MuiButtonBase-root MuiIconButton-root MuiIconButton-sizeSmall css-1rmx1rm" tabindex="0" type="button" aria-label="Toggle code wrap"><svg class="MuiSvgIcon-root MuiSvgIcon-fontSizeInherit css-1cw4hi4" focusable="false" aria-hidden="true" viewbox="0 0 24 24" data-testid="WrapTextIcon"><path d="M4 19h6v-2H4v2zM20 5H4v2h16V5zm-3 6H4v2h13.25c1.1 0 2 .9 2 2s-.9 2-2 2H15v-2l-3 3 3 3v-2h2c2.21 0 4-1.79 4-4s-1.79-4-4-4z"/></svg></button><button class="MuiButtonBase-root MuiIconButton-root MuiIconButton-sizeSmall css-fxo539" tabindex="0" type="button" aria-label="copy"><svg class="MuiSvgIcon-root MuiSvgIcon-fontSizeInherit css-1cw4hi4" focusable="false" aria-hidden="true" viewbox="0 0 24 24" data-testid="ContentCopyIcon"><path d="M16 1H4c-1.1 0-2 .9-2 2v14h2V3h12V1zm3 4H8c-1.1 0-2 .9-2 2v14c0 1.1.9 2 2 2h11c1.1 0 2-.9 2-2V7c0-1.1-.9-2-2-2zm0 16H8V7h11v14z"/></svg></button></code></pre><pre><code class="hljs language-"><div class="MuiBox-root css-1qhimia">Query OK, 0 rows affected (0.09 sec) </div><button class="MuiButtonBase-root MuiIconButton-root MuiIconButton-sizeSmall css-1rmx1rm" tabindex="0" type="button" aria-label="Toggle code wrap"><svg class="MuiSvgIcon-root MuiSvgIcon-fontSizeInherit css-1cw4hi4" focusable="false" aria-hidden="true" viewbox="0 0 24 24" data-testid="WrapTextIcon"><path d="M4 19h6v-2H4v2zM20 5H4v2h16V5zm-3 6H4v2h13.25c1.1 0 2 .9 2 2s-.9 2-2 2H15v-2l-3 3 3 3v-2h2c2.21 0 4-1.79 4-4s-1.79-4-4-4z"/></svg></button><button class="MuiButtonBase-root MuiIconButton-root MuiIconButton-sizeSmall css-fxo539" tabindex="0" type="button" aria-label="copy"><svg class="MuiSvgIcon-root MuiSvgIcon-fontSizeInherit css-1cw4hi4" focusable="false" aria-hidden="true" viewbox="0 0 24 24" data-testid="ContentCopyIcon"><path d="M16 1H4c-1.1 0-2 .9-2 2v14h2V3h12V1zm3 4H8c-1.1 0-2 .9-2 2v14c0 1.1.9 2 2 2h11c1.1 0 2-.9 2-2V7c0-1.1-.9-2-2-2zm0 16H8V7h11v14z"/></svg></button></code></pre><pre><code class="hljs language-sql"><div class="MuiBox-root css-1qhimia"><span class="hljs-keyword">select</span> <span class="hljs-operator">*</span> <span class="hljs-keyword">from</span> t1 <span class="hljs-keyword">partition</span>(p0); </div><button class="MuiButtonBase-root MuiIconButton-root MuiIconButton-sizeSmall css-1rmx1rm" tabindex="0" type="button" aria-label="Toggle code wrap"><svg class="MuiSvgIcon-root MuiSvgIcon-fontSizeInherit css-1cw4hi4" focusable="false" aria-hidden="true" viewbox="0 0 24 24" data-testid="WrapTextIcon"><path d="M4 19h6v-2H4v2zM20 5H4v2h16V5zm-3 6H4v2h13.25c1.1 0 2 .9 2 2s-.9 2-2 2H15v-2l-3 3 3 3v-2h2c2.21 0 4-1.79 4-4s-1.79-4-4-4z"/></svg></button><button class="MuiButtonBase-root MuiIconButton-root MuiIconButton-sizeSmall css-fxo539" tabindex="0" type="button" aria-label="copy"><svg class="MuiSvgIcon-root MuiSvgIcon-fontSizeInherit css-1cw4hi4" focusable="false" aria-hidden="true" viewbox="0 0 24 24" data-testid="ContentCopyIcon"><path d="M16 1H4c-1.1 0-2 .9-2 2v14h2V3h12V1zm3 4H8c-1.1 0-2 .9-2 2v14c0 1.1.9 2 2 2h11c1.1 0 2-.9 2-2V7c0-1.1-.9-2-2-2zm0 16H8V7h11v14z"/></svg></button></code></pre><pre><code class="hljs language-"><div class="MuiBox-root css-1qhimia">+------|--------+ | c1 | c2 | +------|--------+ | NULL | mothra | +------|--------+ 1 row in set (0.00 sec) </div><button class="MuiButtonBase-root MuiIconButton-root MuiIconButton-sizeSmall css-1rmx1rm" tabindex="0" type="button" aria-label="Toggle code wrap"><svg class="MuiSvgIcon-root MuiSvgIcon-fontSizeInherit css-1cw4hi4" focusable="false" aria-hidden="true" viewbox="0 0 24 24" data-testid="WrapTextIcon"><path d="M4 19h6v-2H4v2zM20 5H4v2h16V5zm-3 6H4v2h13.25c1.1 0 2 .9 2 2s-.9 2-2 2H15v-2l-3 3 3 3v-2h2c2.21 0 4-1.79 4-4s-1.79-4-4-4z"/></svg></button><button class="MuiButtonBase-root MuiIconButton-root MuiIconButton-sizeSmall css-fxo539" tabindex="0" type="button" aria-label="copy"><svg class="MuiSvgIcon-root MuiSvgIcon-fontSizeInherit css-1cw4hi4" focusable="false" aria-hidden="true" viewbox="0 0 24 24" data-testid="ContentCopyIcon"><path d="M16 1H4c-1.1 0-2 .9-2 2v14h2V3h12V1zm3 4H8c-1.1 0-2 .9-2 2v14c0 1.1.9 2 2 2h11c1.1 0 2-.9 2-2V7c0-1.1-.9-2-2-2zm0 16H8V7h11v14z"/></svg></button></code></pre><pre><code class="hljs language-sql"><div class="MuiBox-root css-1qhimia"><span class="hljs-keyword">select</span> <span class="hljs-operator">*</span> <span class="hljs-keyword">from</span> t1 <span class="hljs-keyword">partition</span>(p1); </div><button class="MuiButtonBase-root MuiIconButton-root MuiIconButton-sizeSmall css-1rmx1rm" tabindex="0" type="button" aria-label="Toggle code wrap"><svg class="MuiSvgIcon-root MuiSvgIcon-fontSizeInherit css-1cw4hi4" focusable="false" aria-hidden="true" viewbox="0 0 24 24" data-testid="WrapTextIcon"><path d="M4 19h6v-2H4v2zM20 5H4v2h16V5zm-3 6H4v2h13.25c1.1 0 2 .9 2 2s-.9 2-2 2H15v-2l-3 3 3 3v-2h2c2.21 0 4-1.79 4-4s-1.79-4-4-4z"/></svg></button><button class="MuiButtonBase-root MuiIconButton-root MuiIconButton-sizeSmall css-fxo539" tabindex="0" type="button" aria-label="copy"><svg class="MuiSvgIcon-root MuiSvgIcon-fontSizeInherit css-1cw4hi4" focusable="false" aria-hidden="true" viewbox="0 0 24 24" data-testid="ContentCopyIcon"><path d="M16 1H4c-1.1 0-2 .9-2 2v14h2V3h12V1zm3 4H8c-1.1 0-2 .9-2 2v14c0 1.1.9 2 2 2h11c1.1 0 2-.9 2-2V7c0-1.1-.9-2-2-2zm0 16H8V7h11v14z"/></svg></button></code></pre><pre><code class="hljs language-"><div class="MuiBox-root css-1qhimia">Empty set (0.00 sec) </div><button class="MuiButtonBase-root MuiIconButton-root MuiIconButton-sizeSmall css-1rmx1rm" tabindex="0" type="button" aria-label="Toggle code wrap"><svg class="MuiSvgIcon-root MuiSvgIcon-fontSizeInherit css-1cw4hi4" focusable="false" aria-hidden="true" viewbox="0 0 24 24" data-testid="WrapTextIcon"><path d="M4 19h6v-2H4v2zM20 5H4v2h16V5zm-3 6H4v2h13.25c1.1 0 2 .9 2 2s-.9 2-2 2H15v-2l-3 3 3 3v-2h2c2.21 0 4-1.79 4-4s-1.79-4-4-4z"/></svg></button><button class="MuiButtonBase-root MuiIconButton-root MuiIconButton-sizeSmall css-fxo539" tabindex="0" type="button" aria-label="copy"><svg class="MuiSvgIcon-root MuiSvgIcon-fontSizeInherit css-1cw4hi4" focusable="false" aria-hidden="true" viewbox="0 0 24 24" data-testid="ContentCopyIcon"><path d="M16 1H4c-1.1 0-2 .9-2 2v14h2V3h12V1zm3 4H8c-1.1 0-2 .9-2 2v14c0 1.1.9 2 2 2h11c1.1 0 2-.9 2-2V7c0-1.1-.9-2-2-2zm0 16H8V7h11v14z"/></svg></button></code></pre><pre><code class="hljs language-sql"><div class="MuiBox-root css-1qhimia"><span class="hljs-keyword">select</span> <span class="hljs-operator">*</span> <span class="hljs-keyword">from</span> t1 <span class="hljs-keyword">partition</span>(p2); </div><button class="MuiButtonBase-root MuiIconButton-root MuiIconButton-sizeSmall css-1rmx1rm" tabindex="0" type="button" aria-label="Toggle code wrap"><svg class="MuiSvgIcon-root MuiSvgIcon-fontSizeInherit css-1cw4hi4" focusable="false" aria-hidden="true" viewbox="0 0 24 24" data-testid="WrapTextIcon"><path d="M4 19h6v-2H4v2zM20 5H4v2h16V5zm-3 6H4v2h13.25c1.1 0 2 .9 2 2s-.9 2-2 2H15v-2l-3 3 3 3v-2h2c2.21 0 4-1.79 4-4s-1.79-4-4-4z"/></svg></button><button class="MuiButtonBase-root MuiIconButton-root MuiIconButton-sizeSmall css-fxo539" tabindex="0" type="button" aria-label="copy"><svg class="MuiSvgIcon-root MuiSvgIcon-fontSizeInherit css-1cw4hi4" focusable="false" aria-hidden="true" viewbox="0 0 24 24" data-testid="ContentCopyIcon"><path d="M16 1H4c-1.1 0-2 .9-2 2v14h2V3h12V1zm3 4H8c-1.1 0-2 .9-2 2v14c0 1.1.9 2 2 2h11c1.1 0 2-.9 2-2V7c0-1.1-.9-2-2-2zm0 16H8V7h11v14z"/></svg></button></code></pre><pre><code class="hljs language-"><div class="MuiBox-root css-1qhimia">Empty set (0.00 sec) </div><button class="MuiButtonBase-root MuiIconButton-root MuiIconButton-sizeSmall css-1rmx1rm" tabindex="0" type="button" aria-label="Toggle code wrap"><svg class="MuiSvgIcon-root MuiSvgIcon-fontSizeInherit css-1cw4hi4" focusable="false" aria-hidden="true" viewbox="0 0 24 24" data-testid="WrapTextIcon"><path d="M4 19h6v-2H4v2zM20 5H4v2h16V5zm-3 6H4v2h13.25c1.1 0 2 .9 2 2s-.9 2-2 2H15v-2l-3 3 3 3v-2h2c2.21 0 4-1.79 4-4s-1.79-4-4-4z"/></svg></button><button class="MuiButtonBase-root MuiIconButton-root MuiIconButton-sizeSmall css-fxo539" tabindex="0" type="button" aria-label="copy"><svg class="MuiSvgIcon-root MuiSvgIcon-fontSizeInherit css-1cw4hi4" focusable="false" aria-hidden="true" viewbox="0 0 24 24" data-testid="ContentCopyIcon"><path d="M16 1H4c-1.1 0-2 .9-2 2v14h2V3h12V1zm3 4H8c-1.1 0-2 .9-2 2v14c0 1.1.9 2 2 2h11c1.1 0 2-.9 2-2V7c0-1.1-.9-2-2-2zm0 16H8V7h11v14z"/></svg></button></code></pre><p>删除 <code>p0</code> 后验证：</p><pre><code class="hljs language-sql"><div class="MuiBox-root css-1qhimia"><span class="hljs-keyword">alter</span> <span class="hljs-keyword">table</span> t1 <span class="hljs-keyword">drop</span> <span class="hljs-keyword">partition</span> p0; </div><button class="MuiButtonBase-root MuiIconButton-root MuiIconButton-sizeSmall css-1rmx1rm" tabindex="0" type="button" aria-label="Toggle code wrap"><svg class="MuiSvgIcon-root MuiSvgIcon-fontSizeInherit css-1cw4hi4" focusable="false" aria-hidden="true" viewbox="0 0 24 24" data-testid="WrapTextIcon"><path d="M4 19h6v-2H4v2zM20 5H4v2h16V5zm-3 6H4v2h13.25c1.1 0 2 .9 2 2s-.9 2-2 2H15v-2l-3 3 3 3v-2h2c2.21 0 4-1.79 4-4s-1.79-4-4-4z"/></svg></button><button class="MuiButtonBase-root MuiIconButton-root MuiIconButton-sizeSmall css-fxo539" tabindex="0" type="button" aria-label="copy"><svg class="MuiSvgIcon-root MuiSvgIcon-fontSizeInherit css-1cw4hi4" focusable="false" aria-hidden="true" viewbox="0 0 24 24" data-testid="ContentCopyIcon"><path d="M16 1H4c-1.1 0-2 .9-2 2v14h2V3h12V1zm3 4H8c-1.1 0-2 .9-2 2v14c0 1.1.9 2 2 2h11c1.1 0 2-.9 2-2V7c0-1.1-.9-2-2-2zm0 16H8V7h11v14z"/></svg></button></code></pre><pre><code class="hljs language-"><div class="MuiBox-root css-1qhimia">Query OK, 0 rows affected (0.08 sec) </div><button class="MuiButtonBase-root MuiIconButton-root MuiIconButton-sizeSmall css-1rmx1rm" tabindex="0" type="button" aria-label="Toggle code wrap"><svg class="MuiSvgIcon-root MuiSvgIcon-fontSizeInherit css-1cw4hi4" focusable="false" aria-hidden="true" viewbox="0 0 24 24" data-testid="WrapTextIcon"><path d="M4 19h6v-2H4v2zM20 5H4v2h16V5zm-3 6H4v2h13.25c1.1 0 2 .9 2 2s-.9 2-2 2H15v-2l-3 3 3 3v-2h2c2.21 0 4-1.79 4-4s-1.79-4-4-4z"/></svg></button><button class="MuiButtonBase-root MuiIconButton-root MuiIconButton-sizeSmall css-fxo539" tabindex="0" type="button" aria-label="copy"><svg class="MuiSvgIcon-root MuiSvgIcon-fontSizeInherit css-1cw4hi4" focusable="false" aria-hidden="true" viewbox="0 0 24 24" data-testid="ContentCopyIcon"><path d="M16 1H4c-1.1 0-2 .9-2 2v14h2V3h12V1zm3 4H8c-1.1 0-2 .9-2 2v14c0 1.1.9 2 2 2h11c1.1 0 2-.9 2-2V7c0-1.1-.9-2-2-2zm0 16H8V7h11v14z"/></svg></button></code></pre><pre><code class="hljs language-sql"><div class="MuiBox-root css-1qhimia"><span class="hljs-keyword">select</span> <span class="hljs-operator">*</span> <span class="hljs-keyword">from</span> t1; </div><button class="MuiButtonBase-root MuiIconButton-root MuiIconButton-sizeSmall css-1rmx1rm" tabindex="0" type="button" aria-label="Toggle code wrap"><svg class="MuiSvgIcon-root MuiSvgIcon-fontSizeInherit css-1cw4hi4" focusable="false" aria-hidden="true" viewbox="0 0 24 24" data-testid="WrapTextIcon"><path d="M4 19h6v-2H4v2zM20 5H4v2h16V5zm-3 6H4v2h13.25c1.1 0 2 .9 2 2s-.9 2-2 2H15v-2l-3 3 3 3v-2h2c2.21 0 4-1.79 4-4s-1.79-4-4-4z"/></svg></button><button class="MuiButtonBase-root MuiIconButton-root MuiIconButton-sizeSmall css-fxo539" tabindex="0" type="button" aria-label="copy"><svg class="MuiSvgIcon-root MuiSvgIcon-fontSizeInherit css-1cw4hi4" focusable="false" aria-hidden="true" viewbox="0 0 24 24" data-testid="ContentCopyIcon"><path d="M16 1H4c-1.1 0-2 .9-2 2v14h2V3h12V1zm3 4H8c-1.1 0-2 .9-2 2v14c0 1.1.9 2 2 2h11c1.1 0 2-.9 2-2V7c0-1.1-.9-2-2-2zm0 16H8V7h11v14z"/></svg></button></code></pre><pre><code class="hljs language-"><div class="MuiBox-root css-1qhimia">Empty set (0.00 sec) </div><button class="MuiButtonBase-root MuiIconButton-root MuiIconButton-sizeSmall css-1rmx1rm" tabindex="0" type="button" aria-label="Toggle code wrap"><svg class="MuiSvgIcon-root MuiSvgIcon-fontSizeInherit css-1cw4hi4" focusable="false" aria-hidden="true" viewbox="0 0 24 24" data-testid="WrapTextIcon"><path d="M4 19h6v-2H4v2zM20 5H4v2h16V5zm-3 6H4v2h13.25c1.1 0 2 .9 2 2s-.9 2-2 2H15v-2l-3 3 3 3v-2h2c2.21 0 4-1.79 4-4s-1.79-4-4-4z"/></svg></button><button class="MuiButtonBase-root MuiIconButton-root MuiIconButton-sizeSmall css-fxo539" tabindex="0" type="button" aria-label="copy"><svg class="MuiSvgIcon-root MuiSvgIcon-fontSizeInherit css-1cw4hi4" focusable="false" aria-hidden="true" viewbox="0 0 24 24" data-testid="ContentCopyIcon"><path d="M16 1H4c-1.1 0-2 .9-2 2v14h2V3h12V1zm3 4H8c-1.1 0-2 .9-2 2v14c0 1.1.9 2 2 2h11c1.1 0 2-.9 2-2V7c0-1.1-.9-2-2-2zm0 16H8V7h11v14z"/></svg></button></code></pre><h4 id="hash-分区对-null-的处理" style="position:relative"><a href="#hash-%E5%88%86%E5%8C%BA%E5%AF%B9-null-%E7%9A%84%E5%A4%84%E7%90%86" aria-label="hash 分区对 null 的处理 permalink" class="anchor before"><svg aria-hidden="true" focusable="false" height="16" version="1.1" viewbox="0 0 16 16" width="16"><path fill-rule="evenodd" d="M4 9h1v1H4c-1.5 0-3-1.69-3-3.5S2.55 3 4 3h4c1.45 0 3 1.69 3 3.5 0 1.41-.91 2.72-2 3.25V8.59c.58-.45 1-1.27 1-2.09C10 5.22 8.98 4 8 4H4c-.98 0-2 1.22-2 2.5S3 9 4 9zm9-3h-1v1h1c1 0 2 1.22 2 2.5S13.98 12 13 12H9c-.98 0-2-1.22-2-2.5 0-.83.42-1.64 1-2.09V6.25c-1.09.53-2 1.84-2 3.25C6 11.31 7.55 13 9 13h4c1.45 0 3-1.69 3-3.5S14.5 6 13 6z"/></svg></a>Hash 分区对 NULL 的处理</h4><p>在 Hash 分区中 NULL 值的处理有所不同，如果分区表达式的计算结果为 NULL，它会被当作 0 值处理。</p><pre><code class="hljs language-sql"><div class="MuiBox-root css-1qhimia"><span class="hljs-keyword">CREATE</span> <span class="hljs-keyword">TABLE</span> th ( c1 <span class="hljs-type">INT</span>, c2 <span class="hljs-type">VARCHAR</span>(<span class="hljs-number">20</span>) <span class="hljs-keyword">PARTITION</span> <span class="hljs-keyword">BY</span> HASH(c1) PARTITIONS <span class="hljs-number">2</span>; </div><button class="MuiButtonBase-root MuiIconButton-root MuiIconButton-sizeSmall css-1rmx1rm" tabindex="0" type="button" aria-label="Toggle code wrap"><svg class="MuiSvgIcon-root MuiSvgIcon-fontSizeInherit css-1cw4hi4" focusable="false" aria-hidden="true" viewbox="0 0 24 24" data-testid="WrapTextIcon"><path d="M4 19h6v-2H4v2zM20 5H4v2h16V5zm-3 6H4v2h13.25c1.1 0 2 .9 2 2s-.9 2-2 2H15v-2l-3 3 3 3v-2h2c2.21 0 4-1.79 4-4s-1.79-4-4-4z"/></svg></button><button class="MuiButtonBase-root MuiIconButton-root MuiIconButton-sizeSmall css-fxo539" tabindex="0" type="button" aria-label="copy"><svg class="MuiSvgIcon-root MuiSvgIcon-fontSizeInherit css-1cw4hi4" focusable="false" aria-hidden="true" viewbox="0 0 24 24" data-testid="ContentCopyIcon"><path d="M16 1H4c-1.1 0-2 .9-2 2v14h2V3h12V1zm3 4H8c-1.1 0-2 .9-2 2v14c0 1.1.9 2 2 2h11c1.1 0 2-.9 2-2V7c0-1.1-.9-2-2-2zm0 16H8V7h11v14z"/></svg></button></code></pre><pre><code class="hljs language-"><div class="MuiBox-root css-1qhimia">Query OK, 0 rows affected (0.00 sec) </div><button class="MuiButtonBase-root MuiIconButton-root MuiIconButton-sizeSmall css-1rmx1rm" tabindex="0" type="button" aria-label="Toggle code wrap"><svg class="MuiSvgIcon-root MuiSvgIcon-fontSizeInherit css-1cw4hi4" focusable="false" aria-hidden="true" viewbox="0 0 24 24" data-testid="WrapTextIcon"><path d="M4 19h6v-2H4v2zM20 5H4v2h16V5zm-3 6H4v2h13.25c1.1 0 2 .9 2 2s-.9 2-2 2H15v-2l-3 3 3 3v-2h2c2.21 0 4-1.79 4-4s-1.79-4-4-4z"/></svg></button><button class="MuiButtonBase-root MuiIconButton-root MuiIconButton-sizeSmall css-fxo539" tabindex="0" type="button" aria-label="copy"><svg class="MuiSvgIcon-root MuiSvgIcon-fontSizeInherit css-1cw4hi4" focusable="false" aria-hidden="true" viewbox="0 0 24 24" data-testid="ContentCopyIcon"><path d="M16 1H4c-1.1 0-2 .9-2 2v14h2V3h12V1zm3 4H8c-1.1 0-2 .9-2 2v14c0 1.1.9 2 2 2h11c1.1 0 2-.9 2-2V7c0-1.1-.9-2-2-2zm0 16H8V7h11v14z"/></svg></button></code></pre><pre><code class="hljs language-sql"><div class="MuiBox-root css-1qhimia"><span class="hljs-keyword">INSERT</span> <span class="hljs-keyword">INTO</span> th <span class="hljs-keyword">VALUES</span> (<span class="hljs-keyword">NULL</span>, <span class="hljs-string">'mothra'</span>), (<span class="hljs-number">0</span>, <span class="hljs-string">'gigan'</span>); </div><button class="MuiButtonBase-root MuiIconButton-root MuiIconButton-sizeSmall css-1rmx1rm" tabindex="0" type="button" aria-label="Toggle code wrap"><svg class="MuiSvgIcon-root MuiSvgIcon-fontSizeInherit css-1cw4hi4" focusable="false" aria-hidden="true" viewbox="0 0 24 24" data-testid="WrapTextIcon"><path d="M4 19h6v-2H4v2zM20 5H4v2h16V5zm-3 6H4v2h13.25c1.1 0 2 .9 2 2s-.9 2-2 2H15v-2l-3 3 3 3v-2h2c2.21 0 4-1.79 4-4s-1.79-4-4-4z"/></svg></button><button class="MuiButtonBase-root MuiIconButton-root MuiIconButton-sizeSmall css-fxo539" tabindex="0" type="button" aria-label="copy"><svg class="MuiSvgIcon-root MuiSvgIcon-fontSizeInherit css-1cw4hi4" focusable="false" aria-hidden="true" viewbox="0 0 24 24" data-testid="ContentCopyIcon"><path d="M16 1H4c-1.1 0-2 .9-2 2v14h2V3h12V1zm3 4H8c-1.1 0-2 .9-2 2v14c0 1.1.9 2 2 2h11c1.1 0 2-.9 2-2V7c0-1.1-.9-2-2-2zm0 16H8V7h11v14z"/></svg></button></code></pre><pre><code class="hljs language-"><div class="MuiBox-root css-1qhimia">Query OK, 2 rows affected (0.04 sec) </div><button class="MuiButtonBase-root MuiIconButton-root MuiIconButton-sizeSmall css-1rmx1rm" tabindex="0" type="button" aria-label="Toggle code wrap"><svg class="MuiSvgIcon-root MuiSvgIcon-fontSizeInherit css-1cw4hi4" focusable="false" aria-hidden="true" viewbox="0 0 24 24" data-testid="WrapTextIcon"><path d="M4 19h6v-2H4v2zM20 5H4v2h16V5zm-3 6H4v2h13.25c1.1 0 2 .9 2 2s-.9 2-2 2H15v-2l-3 3 3 3v-2h2c2.21 0 4-1.79 4-4s-1.79-4-4-4z"/></svg></button><button class="MuiButtonBase-root MuiIconButton-root MuiIconButton-sizeSmall css-fxo539" tabindex="0" type="button" aria-label="copy"><svg class="MuiSvgIcon-root MuiSvgIcon-fontSizeInherit css-1cw4hi4" focusable="false" aria-hidden="true" viewbox="0 0 24 24" data-testid="ContentCopyIcon"><path d="M16 1H4c-1.1 0-2 .9-2 2v14h2V3h12V1zm3 4H8c-1.1 0-2 .9-2 2v14c0 1.1.9 2 2 2h11c1.1 0 2-.9 2-2V7c0-1.1-.9-2-2-2zm0 16H8V7h11v14z"/></svg></button></code></pre><pre><code class="hljs language-sql"><div class="MuiBox-root css-1qhimia"><span class="hljs-keyword">select</span> <span class="hljs-operator">*</span> <span class="hljs-keyword">from</span> th <span class="hljs-keyword">partition</span> (p0); </div><button class="MuiButtonBase-root MuiIconButton-root MuiIconButton-sizeSmall css-1rmx1rm" tabindex="0" type="button" aria-label="Toggle code wrap"><svg class="MuiSvgIcon-root MuiSvgIcon-fontSizeInherit css-1cw4hi4" focusable="false" aria-hidden="true" viewbox="0 0 24 24" data-testid="WrapTextIcon"><path d="M4 19h6v-2H4v2zM20 5H4v2h16V5zm-3 6H4v2h13.25c1.1 0 2 .9 2 2s-.9 2-2 2H15v-2l-3 3 3 3v-2h2c2.21 0 4-1.79 4-4s-1.79-4-4-4z"/></svg></button><button class="MuiButtonBase-root MuiIconButton-root MuiIconButton-sizeSmall css-fxo539" tabindex="0" type="button" aria-label="copy"><svg class="MuiSvgIcon-root MuiSvgIcon-fontSizeInherit css-1cw4hi4" focusable="false" aria-hidden="true" viewbox="0 0 24 24" data-testid="ContentCopyIcon"><path d="M16 1H4c-1.1 0-2 .9-2 2v14h2V3h12V1zm3 4H8c-1.1 0-2 .9-2 2v14c0 1.1.9 2 2 2h11c1.1 0 2-.9 2-2V7c0-1.1-.9-2-2-2zm0 16H8V7h11v14z"/></svg></button></code></pre><pre><code class="hljs language-"><div class="MuiBox-root css-1qhimia">+------|--------+ | c1 | c2 | +------|--------+ | NULL | mothra | | 0 | gigan | +------|--------+ 2 rows in set (0.00 sec) </div><button class="MuiButtonBase-root MuiIconButton-root MuiIconButton-sizeSmall css-1rmx1rm" tabindex="0" type="button" aria-label="Toggle code wrap"><svg class="MuiSvgIcon-root MuiSvgIcon-fontSizeInherit css-1cw4hi4" focusable="false" aria-hidden="true" viewbox="0 0 24 24" data-testid="WrapTextIcon"><path d="M4 19h6v-2H4v2zM20 5H4v2h16V5zm-3 6H4v2h13.25c1.1 0 2 .9 2 2s-.9 2-2 2H15v-2l-3 3 3 3v-2h2c2.21 0 4-1.79 4-4s-1.79-4-4-4z"/></svg></button><button class="MuiButtonBase-root MuiIconButton-root MuiIconButton-sizeSmall css-fxo539" tabindex="0" type="button" aria-label="copy"><svg class="MuiSvgIcon-root MuiSvgIcon-fontSizeInherit css-1cw4hi4" focusable="false" aria-hidden="true" viewbox="0 0 24 24" data-testid="ContentCopyIcon"><path d="M16 1H4c-1.1 0-2 .9-2 2v14h2V3h12V1zm3 4H8c-1.1 0-2 .9-2 2v14c0 1.1.9 2 2 2h11c1.1 0 2-.9 2-2V7c0-1.1-.9-2-2-2zm0 16H8V7h11v14z"/></svg></button></code></pre><pre><code class="hljs language-sql"><div class="MuiBox-root css-1qhimia"><span class="hljs-keyword">select</span> <span class="hljs-operator">*</span> <span class="hljs-keyword">from</span> th <span class="hljs-keyword">partition</span> (p1); </div><button class="MuiButtonBase-root MuiIconButton-root MuiIconButton-sizeSmall css-1rmx1rm" tabindex="0" type="button" aria-label="Toggle code wrap"><svg class="MuiSvgIcon-root MuiSvgIcon-fontSizeInherit css-1cw4hi4" focusable="false" aria-hidden="true" viewbox="0 0 24 24" data-testid="WrapTextIcon"><path d="M4 19h6v-2H4v2zM20 5H4v2h16V5zm-3 6H4v2h13.25c1.1 0 2 .9 2 2s-.9 2-2 2H15v-2l-3 3 3 3v-2h2c2.21 0 4-1.79 4-4s-1.79-4-4-4z"/></svg></button><button class="MuiButtonBase-root MuiIconButton-root MuiIconButton-sizeSmall css-fxo539" tabindex="0" type="button" aria-label="copy"><svg class="MuiSvgIcon-root MuiSvgIcon-fontSizeInherit css-1cw4hi4" focusable="false" aria-hidden="true" viewbox="0 0 24 24" data-testid="ContentCopyIcon"><path d="M16 1H4c-1.1 0-2 .9-2 2v14h2V3h12V1zm3 4H8c-1.1 0-2 .9-2 2v14c0 1.1.9 2 2 2h11c1.1 0 2-.9 2-2V7c0-1.1-.9-2-2-2zm0 16H8V7h11v14z"/></svg></button></code></pre><pre><code class="hljs language-"><div class="MuiBox-root css-1qhimia">Empty set (0.00 sec) </div><button class="MuiButtonBase-root MuiIconButton-root MuiIconButton-sizeSmall css-1rmx1rm" tabindex="0" type="button" aria-label="Toggle code wrap"><svg class="MuiSvgIcon-root MuiSvgIcon-fontSizeInherit css-1cw4hi4" focusable="false" aria-hidden="true" viewbox="0 0 24 24" data-testid="WrapTextIcon"><path d="M4 19h6v-2H4v2zM20 5H4v2h16V5zm-3 6H4v2h13.25c1.1 0 2 .9 2 2s-.9 2-2 2H15v-2l-3 3 3 3v-2h2c2.21 0 4-1.79 4-4s-1.79-4-4-4z"/></svg></button><button class="MuiButtonBase-root MuiIconButton-root MuiIconButton-sizeSmall css-fxo539" tabindex="0" type="button" aria-label="copy"><svg class="MuiSvgIcon-root MuiSvgIcon-fontSizeInherit css-1cw4hi4" focusable="false" aria-hidden="true" viewbox="0 0 24 24" data-testid="ContentCopyIcon"><path d="M16 1H4c-1.1 0-2 .9-2 2v14h2V3h12V1zm3 4H8c-1.1 0-2 .9-2 2v14c0 1.1.9 2 2 2h11c1.1 0 2-.9 2-2V7c0-1.1-.9-2-2-2zm0 16H8V7h11v14z"/></svg></button></code></pre><p>可以看到，插入的记录 <code>(NULL, 'mothra')</code> 跟 <code>(0, 'gigan')</code> 落在了同一个分区。</p><div class="MuiBox-root css-1weqspv"><div class="MuiPaper-root MuiPaper-elevation MuiPaper-rounded MuiPaper-elevation0 MuiAlert-root MuiAlert-standardInfo MuiAlert-standard css-152gid5" role="alert"><div class="MuiAlert-icon css-1l54tgj"><svg class="MuiSvgIcon-root MuiSvgIcon-fontSizeInherit css-1cw4hi4" focusable="false" aria-hidden="true" viewbox="0 0 24 24" data-testid="InfoOutlinedIcon"><path d="M11,9H13V7H11M12,20C7.59,20 4,16.41 4,12C4,7.59 7.59,4 12,4C16.41,4 20,7.59 20, 12C20,16.41 16.41,20 12,20M12,2A10,10 0 0,0 2,12A10,10 0 0,0 12,22A10,10 0 0,0 22,12A10, 10 0 0,0 12,2M11,17H13V11H11V17Z"/></svg></div><div class="MuiAlert-message css-1xsto0d"><div class="MuiTypography-root MuiTypography-body1 MuiTypography-gutterBottom MuiAlertTitle-root css-17ioyuk">注意</div><p>这里 Hash 分区对 NULL 的处理跟 <a href="https://dev.mysql.com/doc/refman/8.0/en/partitioning-handling-nulls.html" target="_blank" referrerpolicy="no-referrer-when-downgrade">MySQL 的文档描述</a>一致，但是跟 MySQL 的实际行为并不一致。也就是说，MySQL 的文档跟它的实现并不一致。</p><p>TiDB 的最终行为以本文档描述为准。</p></div></div></div><h4 id="key-分区对-null-的处理" style="position:relative"><a href="#key-%E5%88%86%E5%8C%BA%E5%AF%B9-null-%E7%9A%84%E5%A4%84%E7%90%86" aria-label="key 分区对 null 的处理 permalink" class="anchor before"><svg aria-hidden="true" focusable="false" height="16" version="1.1" viewbox="0 0 16 16" width="16"><path fill-rule="evenodd" d="M4 9h1v1H4c-1.5 0-3-1.69-3-3.5S2.55 3 4 3h4c1.45 0 3 1.69 3 3.5 0 1.41-.91 2.72-2 3.25V8.59c.58-.45 1-1.27 1-2.09C10 5.22 8.98 4 8 4H4c-.98 0-2 1.22-2 2.5S3 9 4 9zm9-3h-1v1h1c1 0 2 1.22 2 2.5S13.98 12 13 12H9c-.98 0-2-1.22-2-2.5 0-.83.42-1.64 1-2.09V6.25c-1.09.53-2 1.84-2 3.25C6 11.31 7.55 13 9 13h4c1.45 0 3-1.69 3-3.5S14.5 6 13 6z"/></svg></a>Key 分区对 NULL 的处理</h4><p>在 Key 分区中 NULL 值的处理与 Hash 分区一致：如果分区字段的值为 NULL，它会被当作 0 值处理。</p><h2 id="分区管理" style="position:relative"><a href="#%E5%88%86%E5%8C%BA%E7%AE%A1%E7%90%86" aria-label="分区管理 permalink" class="anchor before"><svg aria-hidden="true" focusable="false" height="16" version="1.1" viewbox="0 0 16 16" width="16"><path fill-rule="evenodd" d="M4 9h1v1H4c-1.5 0-3-1.69-3-3.5S2.55 3 4 3h4c1.45 0 3 1.69 3 3.5 0 1.41-.91 2.72-2 3.25V8.59c.58-.45 1-1.27 1-2.09C10 5.22 8.98 4 8 4H4c-.98 0-2 1.22-2 2.5S3 9 4 9zm9-3h-1v1h1c1 0 2 1.22 2 2.5S13.98 12 13 12H9c-.98 0-2-1.22-2-2.5 0-.83.42-1.64 1-2.09V6.25c-1.09.53-2 1.84-2 3.25C6 11.31 7.55 13 9 13h4c1.45 0 3-1.69 3-3.5S14.5 6 13 6z"/></svg></a>分区管理</h2><p>对于 <code>RANGE</code>、<code>RANGE COLUMNS</code>、<code>LIST</code>、<code>LIST COLUMNS</code> 分区表，你可以进行以下分区管理操作：</p><ul><li>使用 <code>ALTER TABLE &lt;表名&gt; ADD PARTITION (&lt;分区说明&gt;)</code> 语句添加分区。</li><li>使用 <code>ALTER TABLE &lt;表名&gt; DROP PARTITION &lt;分区列表&gt;</code> 删除分区。</li><li>使用 <code>ALTER TABLE &lt;表名&gt; TRUNCATE PARTITION &lt;分区列表&gt;</code> 语句清空分区里的数据。<code>TRUNCATE PARTITION</code> 的逻辑与 <a href="/zh/tidb/stable/sql-statement-truncate"><code>TRUNCATE TABLE</code></a> 相似，但它的操作对象为分区。</li><li>使用 <code>ALTER TABLE &lt;表名&gt; REORGANIZE PARTITION &lt;分区列表&gt; INTO (&lt;新的分区说明&gt;)</code>语句对分区进行合并、拆分、或者其他修改。</li></ul><p>对于 <code>HASH</code> 和 <code>KEY</code> 分区表，你可以进行以下分区管理操作：</p><ul><li>使用 <code>ALTER TABLE &lt;table name&gt; COALESCE PARTITION &lt;要减少的分区数量&gt;</code> 语句减少分区数量。此操作会重组分区，将所有数据按照新的分区个数复制到对应的分区。</li><li>使用 <code>ALTER TABLE &lt;table name&gt; ADD PARTITION &lt;要增加的分区数量 | (新的分区说明)&gt;</code> 语句增加分区的数量。此操作会重组分区，将所有数据按照新的分区个数复制到对应的分区。</li><li>使用 <code>ALTER TABLE &lt;table name&gt; TRUNCATE PARTITION &lt;分区列表&gt;</code> 语句清空分区里的数据。<code>TRUNCATE PARTITION</code> 的逻辑与 <a href="/zh/tidb/stable/sql-statement-truncate"><code>TRUNCATE TABLE</code></a> 相似，但它的操作对象为分区。</li></ul><p><code>EXCHANGE PARTITION</code> 语句用来交换分区和非分区表，类似于重命名表如 <code>RENAME TABLE t1 TO t1_tmp, t2 TO t1, t1_tmp TO t2</code> 的操作。</p><p>例如，<code>ALTER TABLE partitioned_table EXCHANGE PARTITION p1 WITH TABLE non_partitioned_table</code> 交换的是 <code>p1</code> 分区的 <code>partitioned_table</code> 表和 <code>non_partitioned_table</code> 表。</p><p>确保要交换入分区中的所有行与分区定义匹配；否则，交换将失败。</p><p>请注意对于以下 TiDB 专有的特性，当表结构中包含这些特性时，在 TiDB 中使用 <code>EXCHANGE PARTITION</code> 功能不仅需要满足 <a href="https://dev.mysql.com/doc/refman/8.0/en/partitioning-management-exchange.html" target="_blank" referrerpolicy="no-referrer-when-downgrade">MySQL 的 EXCHANGE PARTITION 条件</a>，还要保证这些专有特性对于分区表和非分区表的定义相同。</p><ul><li><a href="/zh/tidb/stable/placement-rules-in-sql">Placement Rules in SQL</a>：Placement Policy 定义相同。</li><li><a href="/zh/tidb/stable/tiflash-overview">TiFlash</a>：TiFlash Replica 数量相同。</li><li><a href="/zh/tidb/stable/clustered-indexes">聚簇索引</a>：分区表和非分区表要么都是聚簇索引 (CLUSTERED)，要么都不是聚簇索引 (NONCLUSTERED)。</li></ul><p>此外，<code>EXCHANGE PARTITION</code> 和其他组件兼容性上存在一些限制，需要保证分区表和非分区表的一致性：</p><ul><li>TiFlash：TiFlash Replica 定义不同时，无法执行 <code>EXCHANGE PARTITION</code> 操作。</li><li>TiCDC：分区表和非分区表都有主键或者唯一键时，TiCDC 同步 <code>EXCHANGE PARTITION</code> 操作；反之 TiCDC 将不会同步。</li><li>TiDB Lightning 和 BR：使用 TiDB Lightning 导入或使用 BR 恢复的过程中，不要执行 <code>EXCHANGE PARTITION</code> 操作。</li></ul><h3 id="管理-list-分区list-columns-分区range-分区range-columns-分区" style="position:relative"><a href="#%E7%AE%A1%E7%90%86-list-%E5%88%86%E5%8C%BAlist-columns-%E5%88%86%E5%8C%BArange-%E5%88%86%E5%8C%BArange-columns-%E5%88%86%E5%8C%BA" aria-label="管理 list 分区list columns 分区range 分区range columns 分区 permalink" class="anchor before"><svg aria-hidden="true" focusable="false" height="16" version="1.1" viewbox="0 0 16 16" width="16"><path fill-rule="evenodd" d="M4 9h1v1H4c-1.5 0-3-1.69-3-3.5S2.55 3 4 3h4c1.45 0 3 1.69 3 3.5 0 1.41-.91 2.72-2 3.25V8.59c.58-.45 1-1.27 1-2.09C10 5.22 8.98 4 8 4H4c-.98 0-2 1.22-2 2.5S3 9 4 9zm9-3h-1v1h1c1 0 2 1.22 2 2.5S13.98 12 13 12H9c-.98 0-2-1.22-2-2.5 0-.83.42-1.64 1-2.09V6.25c-1.09.53-2 1.84-2 3.25C6 11.31 7.55 13 9 13h4c1.45 0 3-1.69 3-3.5S14.5 6 13 6z"/></svg></a>管理 List 分区、List COLUMNS 分区、Range 分区、Range COLUMNS 分区</h3><p>本小节将以如下 SQL 语句创建的分区表为例，介绍如何管理 Range 分区和 List 分区。</p><pre><code class="hljs language-sql"><div class="MuiBox-root css-1qhimia"><span class="hljs-keyword">CREATE</span> <span class="hljs-keyword">TABLE</span> members ( id <span class="hljs-type">int</span>, fname <span class="hljs-type">varchar</span>(<span class="hljs-number">255</span>), lname <span class="hljs-type">varchar</span>(<span class="hljs-number">255</span>), dob <span class="hljs-type">date</span>, data json <span class="hljs-keyword">PARTITION</span> <span class="hljs-keyword">BY</span> <span class="hljs-keyword">RANGE</span> (<span class="hljs-keyword">YEAR</span>(dob)) ( <span class="hljs-keyword">PARTITION</span> pBefore1950 <span class="hljs-keyword">VALUES</span> LESS THAN (<span class="hljs-number">1950</span>), <span class="hljs-keyword">PARTITION</span> p1950 <span class="hljs-keyword">VALUES</span> LESS THAN (<span class="hljs-number">1960</span>), <span class="hljs-keyword">PARTITION</span> p1960 <span class="hljs-keyword">VALUES</span> LESS THAN (<span class="hljs-number">1970</span>), <span class="hljs-keyword">PARTITION</span> p1970 <span class="hljs-keyword">VALUES</span> LESS THAN (<span class="hljs-number">1980</span>), <span class="hljs-keyword">PARTITION</span> p1980 <span class="hljs-keyword">VALUES</span> LESS THAN (<span class="hljs-number">1990</span>), <span class="hljs-keyword">PARTITION</span> p1990 <span class="hljs-keyword">VALUES</span> LESS THAN (<span class="hljs-number">2000</span>)); <span class="hljs-keyword">CREATE</span> <span class="hljs-keyword">TABLE</span> member_level ( id <span class="hljs-type">int</span>, level <span class="hljs-type">int</span>, achievements json <span class="hljs-keyword">PARTITION</span> <span class="hljs-keyword">BY</span> LIST (level) ( <span class="hljs-keyword">PARTITION</span> l1 <span class="hljs-keyword">VALUES</span> <span class="hljs-keyword">IN</span> (<span class="hljs-number">1</span>), <span class="hljs-keyword">PARTITION</span> l2 <span class="hljs-keyword">VALUES</span> <span class="hljs-keyword">IN</span> (<span class="hljs-number">2</span>), <span class="hljs-keyword">PARTITION</span> l3 <span class="hljs-keyword">VALUES</span> <span class="hljs-keyword">IN</span> (<span class="hljs-number">3</span>), <span class="hljs-keyword">PARTITION</span> l4 <span class="hljs-keyword">VALUES</span> <span class="hljs-keyword">IN</span> (<span class="hljs-number">4</span>), <span class="hljs-keyword">PARTITION</span> l5 <span class="hljs-keyword">VALUES</span> <span class="hljs-keyword">IN</span> (<span class="hljs-number">5</span>)); </div><button class="MuiButtonBase-root MuiIconButton-root MuiIconButton-sizeSmall css-1rmx1rm" tabindex="0" type="button" aria-label="Toggle code wrap"><svg class="MuiSvgIcon-root MuiSvgIcon-fontSizeInherit css-1cw4hi4" focusable="false" aria-hidden="true" viewbox="0 0 24 24" data-testid="WrapTextIcon"><path d="M4 19h6v-2H4v2zM20 5H4v2h16V5zm-3 6H4v2h13.25c1.1 0 2 .9 2 2s-.9 2-2 2H15v-2l-3 3 3 3v-2h2c2.21 0 4-1.79 4-4s-1.79-4-4-4z"/></svg></button><button class="MuiButtonBase-root MuiIconButton-root MuiIconButton-sizeSmall css-fxo539" tabindex="0" type="button" aria-label="copy"><svg class="MuiSvgIcon-root MuiSvgIcon-fontSizeInherit css-1cw4hi4" focusable="false" aria-hidden="true" viewbox="0 0 24 24" data-testid="ContentCopyIcon"><path d="M16 1H4c-1.1 0-2 .9-2 2v14h2V3h12V1zm3 4H8c-1.1 0-2 .9-2 2v14c0 1.1.9 2 2 2h11c1.1 0 2-.9 2-2V7c0-1.1-.9-2-2-2zm0 16H8V7h11v14z"/></svg></button></code></pre><h4 id="删除分区" style="position:relative"><a href="#%E5%88%A0%E9%99%A4%E5%88%86%E5%8C%BA" aria-label="删除分区 permalink" class="anchor before"><svg aria-hidden="true" focusable="false" height="16" version="1.1" viewbox="0 0 16 16" width="16"><path fill-rule="evenodd" d="M4 9h1v1H4c-1.5 0-3-1.69-3-3.5S2.55 3 4 3h4c1.45 0 3 1.69 3 3.5 0 1.41-.91 2.72-2 3.25V8.59c.58-.45 1-1.27 1-2.09C10 5.22 8.98 4 8 4H4c-.98 0-2 1.22-2 2.5S3 9 4 9zm9-3h-1v1h1c1 0 2 1.22 2 2.5S13.98 12 13 12H9c-.98 0-2-1.22-2-2.5 0-.83.42-1.64 1-2.09V6.25c-1.09.53-2 1.84-2 3.25C6 11.31 7.55 13 9 13h4c1.45 0 3-1.69 3-3.5S14.5 6 13 6z"/></svg></a>删除分区</h4><pre><code class="hljs language-sql"><div class="MuiBox-root css-1qhimia"><span class="hljs-keyword">ALTER</span> <span class="hljs-keyword">TABLE</span> members <span class="hljs-keyword">DROP</span> <span class="hljs-keyword">PARTITION</span> p1990; <span class="hljs-keyword">ALTER</span> <span class="hljs-keyword">TABLE</span> member_level <span class="hljs-keyword">DROP</span> <span class="hljs-keyword">PARTITION</span> l5; </div><button class="MuiButtonBase-root MuiIconButton-root MuiIconButton-sizeSmall css-1rmx1rm" tabindex="0" type="button" aria-label="Toggle code wrap"><svg class="MuiSvgIcon-root MuiSvgIcon-fontSizeInherit css-1cw4hi4" focusable="false" aria-hidden="true" viewbox="0 0 24 24" data-testid="WrapTextIcon"><path d="M4 19h6v-2H4v2zM20 5H4v2h16V5zm-3 6H4v2h13.25c1.1 0 2 .9 2 2s-.9 2-2 2H15v-2l-3 3 3 3v-2h2c2.21 0 4-1.79 4-4s-1.79-4-4-4z"/></svg></button><button class="MuiButtonBase-root MuiIconButton-root MuiIconButton-sizeSmall css-fxo539" tabindex="0" type="button" aria-label="copy"><svg class="MuiSvgIcon-root MuiSvgIcon-fontSizeInherit css-1cw4hi4" focusable="false" aria-hidden="true" viewbox="0 0 24 24" data-testid="ContentCopyIcon"><path d="M16 1H4c-1.1 0-2 .9-2 2v14h2V3h12V1zm3 4H8c-1.1 0-2 .9-2 2v14c0 1.1.9 2 2 2h11c1.1 0 2-.9 2-2V7c0-1.1-.9-2-2-2zm0 16H8V7h11v14z"/></svg></button></code></pre><h4 id="清空分区" style="position:relative"><a href="#%E6%B8%85%E7%A9%BA%E5%88%86%E5%8C%BA" aria-label="清空分区 permalink" class="anchor before"><svg aria-hidden="true" focusable="false" height="16" version="1.1" viewbox="0 0 16 16" width="16"><path fill-rule="evenodd" d="M4 9h1v1H4c-1.5 0-3-1.69-3-3.5S2.55 3 4 3h4c1.45 0 3 1.69 3 3.5 0 1.41-.91 2.72-2 3.25V8.59c.58-.45 1-1.27 1-2.09C10 5.22 8.98 4 8 4H4c-.98 0-2 1.22-2 2.5S3 9 4 9zm9-3h-1v1h1c1 0 2 1.22 2 2.5S13.98 12 13 12H9c-.98 0-2-1.22-2-2.5 0-.83.42-1.64 1-2.09V6.25c-1.09.53-2 1.84-2 3.25C6 11.31 7.55 13 9 13h4c1.45 0 3-1.69 3-3.5S14.5 6 13 6z"/></svg></a>清空分区</h4><pre><code class="hljs language-sql"><div class="MuiBox-root css-1qhimia"><span class="hljs-keyword">ALTER</span> <span class="hljs-keyword">TABLE</span> members <span class="hljs-keyword">TRUNCATE</span> <span class="hljs-keyword">PARTITION</span> p1980; <span class="hljs-keyword">ALTER</span> <span class="hljs-keyword">TABLE</span> member_level <span class="hljs-keyword">TRUNCATE</span> <span class="hljs-keyword">PARTITION</span> l4; </div><button class="MuiButtonBase-root MuiIconButton-root MuiIconButton-sizeSmall css-1rmx1rm" tabindex="0" type="button" aria-label="Toggle code wrap"><svg class="MuiSvgIcon-root MuiSvgIcon-fontSizeInherit css-1cw4hi4" focusable="false" aria-hidden="true" viewbox="0 0 24 24" data-testid="WrapTextIcon"><path d="M4 19h6v-2H4v2zM20 5H4v2h16V5zm-3 6H4v2h13.25c1.1 0 2 .9 2 2s-.9 2-2 2H15v-2l-3 3 3 3v-2h2c2.21 0 4-1.79 4-4s-1.79-4-4-4z"/></svg></button><button class="MuiButtonBase-root MuiIconButton-root MuiIconButton-sizeSmall css-fxo539" tabindex="0" type="button" aria-label="copy"><svg class="MuiSvgIcon-root MuiSvgIcon-fontSizeInherit css-1cw4hi4" focusable="false" aria-hidden="true" viewbox="0 0 24 24" data-testid="ContentCopyIcon"><path d="M16 1H4c-1.1 0-2 .9-2 2v14h2V3h12V1zm3 4H8c-1.1 0-2 .9-2 2v14c0 1.1.9 2 2 2h11c1.1 0 2-.9 2-2V7c0-1.1-.9-2-2-2zm0 16H8V7h11v14z"/></svg></button></code></pre><h4 id="添加分区" style="position:relative"><a href="#%E6%B7%BB%E5%8A%A0%E5%88%86%E5%8C%BA" aria-label="添加分区 permalink" class="anchor before"><svg aria-hidden="true" focusable="false" height="16" version="1.1" viewbox="0 0 16 16" width="16"><path fill-rule="evenodd" d="M4 9h1v1H4c-1.5 0-3-1.69-3-3.5S2.55 3 4 3h4c1.45 0 3 1.69 3 3.5 0 1.41-.91 2.72-2 3.25V8.59c.58-.45 1-1.27 1-2.09C10 5.22 8.98 4 8 4H4c-.98 0-2 1.22-2 2.5S3 9 4 9zm9-3h-1v1h1c1 0 2 1.22 2 2.5S13.98 12 13 12H9c-.98 0-2-1.22-2-2.5 0-.83.42-1.64 1-2.09V6.25c-1.09.53-2 1.84-2 3.25C6 11.31 7.55 13 9 13h4c1.45 0 3-1.69 3-3.5S14.5 6 13 6z"/></svg></a>添加分区</h4><pre><code class="hljs language-sql"><div class="MuiBox-root css-1qhimia"><span class="hljs-keyword">ALTER</span> <span class="hljs-keyword">TABLE</span> members <span class="hljs-keyword">ADD</span> <span class="hljs-keyword">PARTITION</span> (<span class="hljs-keyword">PARTITION</span> `p1990to2010` <span class="hljs-keyword">VALUES</span> LESS THAN (<span class="hljs-number">2010</span>)); <span class="hljs-keyword">ALTER</span> <span class="hljs-keyword">TABLE</span> member_level <span class="hljs-keyword">ADD</span> <span class="hljs-keyword">PARTITION</span> (<span class="hljs-keyword">PARTITION</span> l5_6 <span class="hljs-keyword">VALUES</span> <span class="hljs-keyword">IN</span> (<span class="hljs-number">5</span>,<span class="hljs-number">6</span>)); </div><button class="MuiButtonBase-root MuiIconButton-root MuiIconButton-sizeSmall css-1rmx1rm" tabindex="0" type="button" aria-label="Toggle code wrap"><svg class="MuiSvgIcon-root MuiSvgIcon-fontSizeInherit css-1cw4hi4" focusable="false" aria-hidden="true" viewbox="0 0 24 24" data-testid="WrapTextIcon"><path d="M4 19h6v-2H4v2zM20 5H4v2h16V5zm-3 6H4v2h13.25c1.1 0 2 .9 2 2s-.9 2-2 2H15v-2l-3 3 3 3v-2h2c2.21 0 4-1.79 4-4s-1.79-4-4-4z"/></svg></button><button class="MuiButtonBase-root MuiIconButton-root MuiIconButton-sizeSmall css-fxo539" tabindex="0" type="button" aria-label="copy"><svg class="MuiSvgIcon-root MuiSvgIcon-fontSizeInherit css-1cw4hi4" focusable="false" aria-hidden="true" viewbox="0 0 24 24" data-testid="ContentCopyIcon"><path d="M16 1H4c-1.1 0-2 .9-2 2v14h2V3h12V1zm3 4H8c-1.1 0-2 .9-2 2v14c0 1.1.9 2 2 2h11c1.1 0 2-.9 2-2V7c0-1.1-.9-2-2-2zm0 16H8V7h11v14z"/></svg></button></code></pre><p>对于 Range 分区表，<code>ADD PARTITION</code> 只能在分区列表的最后添加新的分区。与分区列表中已有的分区相比，你需要将新分区的 <code>VALUES LESS THAN</code> 定义为更大的值。否则，执行该语句时将会报错。</p><pre><code class="hljs language-sql"><div class="MuiBox-root css-1qhimia"><span class="hljs-keyword">ALTER</span> <span class="hljs-keyword">TABLE</span> members <span class="hljs-keyword">ADD</span> <span class="hljs-keyword">PARTITION</span> (<span class="hljs-keyword">PARTITION</span> p1990 <span class="hljs-keyword">VALUES</span> LESS THAN (<span class="hljs-number">2000</span>)); </div><button class="MuiButtonBase-root MuiIconButton-root MuiIconButton-sizeSmall css-1rmx1rm" tabindex="0" type="button" aria-label="Toggle code wrap"><svg class="MuiSvgIcon-root MuiSvgIcon-fontSizeInherit css-1cw4hi4" focusable="false" aria-hidden="true" viewbox="0 0 24 24" data-testid="WrapTextIcon"><path d="M4 19h6v-2H4v2zM20 5H4v2h16V5zm-3 6H4v2h13.25c1.1 0 2 .9 2 2s-.9 2-2 2H15v-2l-3 3 3 3v-2h2c2.21 0 4-1.79 4-4s-1.79-4-4-4z"/></svg></button><button class="MuiButtonBase-root MuiIconButton-root MuiIconButton-sizeSmall css-fxo539" tabindex="0" type="button" aria-label="copy"><svg class="MuiSvgIcon-root MuiSvgIcon-fontSizeInherit css-1cw4hi4" focusable="false" aria-hidden="true" viewbox="0 0 24 24" data-testid="ContentCopyIcon"><path d="M16 1H4c-1.1 0-2 .9-2 2v14h2V3h12V1zm3 4H8c-1.1 0-2 .9-2 2v14c0 1.1.9 2 2 2h11c1.1 0 2-.9 2-2V7c0-1.1-.9-2-2-2zm0 16H8V7h11v14z"/></svg></button></code></pre><pre><code class="hljs language-"><div class="MuiBox-root css-1qhimia">ERROR 1493 (HY000): VALUES LESS THAN value must be strictly increasing for each partition </div><button class="MuiButtonBase-root MuiIconButton-root MuiIconButton-sizeSmall css-1rmx1rm" tabindex="0" type="button" aria-label="Toggle code wrap"><svg class="MuiSvgIcon-root MuiSvgIcon-fontSizeInherit css-1cw4hi4" focusable="false" aria-hidden="true" viewbox="0 0 24 24" data-testid="WrapTextIcon"><path d="M4 19h6v-2H4v2zM20 5H4v2h16V5zm-3 6H4v2h13.25c1.1 0 2 .9 2 2s-.9 2-2 2H15v-2l-3 3 3 3v-2h2c2.21 0 4-1.79 4-4s-1.79-4-4-4z"/></svg></button><button class="MuiButtonBase-root MuiIconButton-root MuiIconButton-sizeSmall css-fxo539" tabindex="0" type="button" aria-label="copy"><svg class="MuiSvgIcon-root MuiSvgIcon-fontSizeInherit css-1cw4hi4" focusable="false" aria-hidden="true" viewbox="0 0 24 24" data-testid="ContentCopyIcon"><path d="M16 1H4c-1.1 0-2 .9-2 2v14h2V3h12V1zm3 4H8c-1.1 0-2 .9-2 2v14c0 1.1.9 2 2 2h11c1.1 0 2-.9 2-2V7c0-1.1-.9-2-2-2zm0 16H8V7h11v14z"/></svg></button></code></pre><h4 id="重组分区" style="position:relative"><a href="#%E9%87%8D%E7%BB%84%E5%88%86%E5%8C%BA" aria-label="重组分区 permalink" class="anchor before"><svg aria-hidden="true" focusable="false" height="16" version="1.1" viewbox="0 0 16 16" width="16"><path fill-rule="evenodd" d="M4 9h1v1H4c-1.5 0-3-1.69-3-3.5S2.55 3 4 3h4c1.45 0 3 1.69 3 3.5 0 1.41-.91 2.72-2 3.25V8.59c.58-.45 1-1.27 1-2.09C10 5.22 8.98 4 8 4H4c-.98 0-2 1.22-2 2.5S3 9 4 9zm9-3h-1v1h1c1 0 2 1.22 2 2.5S13.98 12 13 12H9c-.98 0-2-1.22-2-2.5 0-.83.42-1.64 1-2.09V6.25c-1.09.53-2 1.84-2 3.25C6 11.31 7.55 13 9 13h4c1.45 0 3-1.69 3-3.5S14.5 6 13 6z"/></svg></a>重组分区</h4><p>拆分分区：</p><pre><code class="hljs language-sql"><div class="MuiBox-root css-1qhimia"><span class="hljs-keyword">ALTER</span> <span class="hljs-keyword">TABLE</span> members REORGANIZE <span class="hljs-keyword">PARTITION</span> `p1990to2010` <span class="hljs-keyword">INTO</span> (<span class="hljs-keyword">PARTITION</span> p1990 <span class="hljs-keyword">VALUES</span> LESS THAN (<span class="hljs-number">2000</span>), <span class="hljs-keyword">PARTITION</span> p2000 <span class="hljs-keyword">VALUES</span> LESS THAN (<span class="hljs-number">2010</span>), <span class="hljs-keyword">PARTITION</span> p2010 <span class="hljs-keyword">VALUES</span> LESS THAN (<span class="hljs-number">2020</span>), <span class="hljs-keyword">PARTITION</span> p2020 <span class="hljs-keyword">VALUES</span> LESS THAN (<span class="hljs-number">2030</span>), <span class="hljs-keyword">PARTITION</span> pMax <span class="hljs-keyword">VALUES</span> LESS THAN (MAXVALUE)); <span class="hljs-keyword">ALTER</span> <span class="hljs-keyword">TABLE</span> member_level REORGANIZE <span class="hljs-keyword">PARTITION</span> l5_6 <span class="hljs-keyword">INTO</span> (<span class="hljs-keyword">PARTITION</span> l5 <span class="hljs-keyword">VALUES</span> <span class="hljs-keyword">IN</span> (<span class="hljs-number">5</span>), <span class="hljs-keyword">PARTITION</span> l6 <span class="hljs-keyword">VALUES</span> <span class="hljs-keyword">IN</span> (<span class="hljs-number">6</span>)); </div><button class="MuiButtonBase-root MuiIconButton-root MuiIconButton-sizeSmall css-1rmx1rm" tabindex="0" type="button" aria-label="Toggle code wrap"><svg class="MuiSvgIcon-root MuiSvgIcon-fontSizeInherit css-1cw4hi4" focusable="false" aria-hidden="true" viewbox="0 0 24 24" data-testid="WrapTextIcon"><path d="M4 19h6v-2H4v2zM20 5H4v2h16V5zm-3 6H4v2h13.25c1.1 0 2 .9 2 2s-.9 2-2 2H15v-2l-3 3 3 3v-2h2c2.21 0 4-1.79 4-4s-1.79-4-4-4z"/></svg></button><button class="MuiButtonBase-root MuiIconButton-root MuiIconButton-sizeSmall css-fxo539" tabindex="0" type="button" aria-label="copy"><svg class="MuiSvgIcon-root MuiSvgIcon-fontSizeInherit css-1cw4hi4" focusable="false" aria-hidden="true" viewbox="0 0 24 24" data-testid="ContentCopyIcon"><path d="M16 1H4c-1.1 0-2 .9-2 2v14h2V3h12V1zm3 4H8c-1.1 0-2 .9-2 2v14c0 1.1.9 2 2 2h11c1.1 0 2-.9 2-2V7c0-1.1-.9-2-2-2zm0 16H8V7h11v14z"/></svg></button></code></pre><p>合并分区：</p><pre><code class="hljs language-sql"><div class="MuiBox-root css-1qhimia"><span class="hljs-keyword">ALTER</span> <span class="hljs-keyword">TABLE</span> members REORGANIZE <span class="hljs-keyword">PARTITION</span> pBefore1950,p1950 <span class="hljs-keyword">INTO</span> (<span class="hljs-keyword">PARTITION</span> pBefore1960 <span class="hljs-keyword">VALUES</span> LESS THAN (<span class="hljs-number">1960</span>)); <span class="hljs-keyword">ALTER</span> <span class="hljs-keyword">TABLE</span> member_level REORGANIZE <span class="hljs-keyword">PARTITION</span> l1,l2 <span class="hljs-keyword">INTO</span> (<span class="hljs-keyword">PARTITION</span> l1_2 <span class="hljs-keyword">VALUES</span> <span class="hljs-keyword">IN</span> (<span class="hljs-number">1</span>,<span class="hljs-number">2</span>)); </div><button class="MuiButtonBase-root MuiIconButton-root MuiIconButton-sizeSmall css-1rmx1rm" tabindex="0" type="button" aria-label="Toggle code wrap"><svg class="MuiSvgIcon-root MuiSvgIcon-fontSizeInherit css-1cw4hi4" focusable="false" aria-hidden="true" viewbox="0 0 24 24" data-testid="WrapTextIcon"><path d="M4 19h6v-2H4v2zM20 5H4v2h16V5zm-3 6H4v2h13.25c1.1 0 2 .9 2 2s-.9 2-2 2H15v-2l-3 3 3 3v-2h2c2.21 0 4-1.79 4-4s-1.79-4-4-4z"/></svg></button><button class="MuiButtonBase-root MuiIconButton-root MuiIconButton-sizeSmall css-fxo539" tabindex="0" type="button" aria-label="copy"><svg class="MuiSvgIcon-root MuiSvgIcon-fontSizeInherit css-1cw4hi4" focusable="false" aria-hidden="true" viewbox="0 0 24 24" data-testid="ContentCopyIcon"><path d="M16 1H4c-1.1 0-2 .9-2 2v14h2V3h12V1zm3 4H8c-1.1 0-2 .9-2 2v14c0 1.1.9 2 2 2h11c1.1 0 2-.9 2-2V7c0-1.1-.9-2-2-2zm0 16H8V7h11v14z"/></svg></button></code></pre><p>修改分区表定义：</p><pre><code class="hljs language-sql"><div class="MuiBox-root css-1qhimia"><span class="hljs-keyword">ALTER</span> <span class="hljs-keyword">TABLE</span> members REORGANIZE <span class="hljs-keyword">PARTITION</span> pBefore1960,p1960,p1970,p1980,p1990,p2000,p2010,p2020,pMax <span class="hljs-keyword">INTO</span> (<span class="hljs-keyword">PARTITION</span> p1800 <span class="hljs-keyword">VALUES</span> LESS THAN (<span class="hljs-number">1900</span>), <span class="hljs-keyword">PARTITION</span> p1900 <span class="hljs-keyword">VALUES</span> LESS THAN (<span class="hljs-number">2000</span>), <span class="hljs-keyword">PARTITION</span> p2000 <span class="hljs-keyword">VALUES</span> LESS THAN (<span class="hljs-number">2100</span>)); <span class="hljs-keyword">ALTER</span> <span class="hljs-keyword">TABLE</span> member_level REORGANIZE <span class="hljs-keyword">PARTITION</span> l1_2,l3,l4,l5,l6 <span class="hljs-keyword">INTO</span> (<span class="hljs-keyword">PARTITION</span> lOdd <span class="hljs-keyword">VALUES</span> <span class="hljs-keyword">IN</span> (<span class="hljs-number">1</span>,<span class="hljs-number">3</span>,<span class="hljs-number">5</span>), <span class="hljs-keyword">PARTITION</span> lEven <span class="hljs-keyword">VALUES</span> <span class="hljs-keyword">IN</span> (<span class="hljs-number">2</span>,<span class="hljs-number">4</span>,<span class="hljs-number">6</span>)); </div><button class="MuiButtonBase-root MuiIconButton-root MuiIconButton-sizeSmall css-1rmx1rm" tabindex="0" type="button" aria-label="Toggle code wrap"><svg class="MuiSvgIcon-root MuiSvgIcon-fontSizeInherit css-1cw4hi4" focusable="false" aria-hidden="true" viewbox="0 0 24 24" data-testid="WrapTextIcon"><path d="M4 19h6v-2H4v2zM20 5H4v2h16V5zm-3 6H4v2h13.25c1.1 0 2 .9 2 2s-.9 2-2 2H15v-2l-3 3 3 3v-2h2c2.21 0 4-1.79 4-4s-1.79-4-4-4z"/></svg></button><button class="MuiButtonBase-root MuiIconButton-root MuiIconButton-sizeSmall css-fxo539" tabindex="0" type="button" aria-label="copy"><svg class="MuiSvgIcon-root MuiSvgIcon-fontSizeInherit css-1cw4hi4" focusable="false" aria-hidden="true" viewbox="0 0 24 24" data-testid="ContentCopyIcon"><path d="M16 1H4c-1.1 0-2 .9-2 2v14h2V3h12V1zm3 4H8c-1.1 0-2 .9-2 2v14c0 1.1.9 2 2 2h11c1.1 0 2-.9 2-2V7c0-1.1-.9-2-2-2zm0 16H8V7h11v14z"/></svg></button></code></pre><p>在重组分区时，需要注意以下关键点：</p><ul><li><p>重组分区（包括合并或拆分分区）只能修改分区定义，无法修改分区表类型。例如，无法将 List 类型修改为 Range 类型，或将 Range COLUMNS 类型修改为 Range 类型。</p></li><li><p>对于 Range 分区表，你只能对表中相邻的分区进行重组：</p><pre><code class="hljs language-sql"><div class="MuiBox-root css-1qhimia"><span class="hljs-keyword">ALTER</span> <span class="hljs-keyword">TABLE</span> members REORGANIZE <span class="hljs-keyword">PARTITION</span> p1800,p2000 <span class="hljs-keyword">INTO</span> (<span class="hljs-keyword">PARTITION</span> p2000 <span class="hljs-keyword">VALUES</span> LESS THAN (<span class="hljs-number">2100</span>)); </div><button class="MuiButtonBase-root MuiIconButton-root MuiIconButton-sizeSmall css-1rmx1rm" tabindex="0" type="button" aria-label="Toggle code wrap"><svg class="MuiSvgIcon-root MuiSvgIcon-fontSizeInherit css-1cw4hi4" focusable="false" aria-hidden="true" viewbox="0 0 24 24" data-testid="WrapTextIcon"><path d="M4 19h6v-2H4v2zM20 5H4v2h16V5zm-3 6H4v2h13.25c1.1 0 2 .9 2 2s-.9 2-2 2H15v-2l-3 3 3 3v-2h2c2.21 0 4-1.79 4-4s-1.79-4-4-4z"/></svg></button><button class="MuiButtonBase-root MuiIconButton-root MuiIconButton-sizeSmall css-fxo539" tabindex="0" type="button" aria-label="copy"><svg class="MuiSvgIcon-root MuiSvgIcon-fontSizeInherit css-1cw4hi4" focusable="false" aria-hidden="true" viewbox="0 0 24 24" data-testid="ContentCopyIcon"><path d="M16 1H4c-1.1 0-2 .9-2 2v14h2V3h12V1zm3 4H8c-1.1 0-2 .9-2 2v14c0 1.1.9 2 2 2h11c1.1 0 2-.9 2-2V7c0-1.1-.9-2-2-2zm0 16H8V7h11v14z"/></svg></button></code></pre><pre><code class="hljs language-"><div class="MuiBox-root css-1qhimia">ERROR 8200 (HY000): Unsupported REORGANIZE PARTITION of RANGE; not adjacent partitions </div><button class="MuiButtonBase-root MuiIconButton-root MuiIconButton-sizeSmall css-1rmx1rm" tabindex="0" type="button" aria-label="Toggle code wrap"><svg class="MuiSvgIcon-root MuiSvgIcon-fontSizeInherit css-1cw4hi4" focusable="false" aria-hidden="true" viewbox="0 0 24 24" data-testid="WrapTextIcon"><path d="M4 19h6v-2H4v2zM20 5H4v2h16V5zm-3 6H4v2h13.25c1.1 0 2 .9 2 2s-.9 2-2 2H15v-2l-3 3 3 3v-2h2c2.21 0 4-1.79 4-4s-1.79-4-4-4z"/></svg></button><button class="MuiButtonBase-root MuiIconButton-root MuiIconButton-sizeSmall css-fxo539" tabindex="0" type="button" aria-label="copy"><svg class="MuiSvgIcon-root MuiSvgIcon-fontSizeInherit css-1cw4hi4" focusable="false" aria-hidden="true" viewbox="0 0 24 24" data-testid="ContentCopyIcon"><path d="M16 1H4c-1.1 0-2 .9-2 2v14h2V3h12V1zm3 4H8c-1.1 0-2 .9-2 2v14c0 1.1.9 2 2 2h11c1.1 0 2-.9 2-2V7c0-1.1-.9-2-2-2zm0 16H8V7h11v14z"/></svg></button></code></pre></li><li><p>对于 Range 分区表，如需修改 Range 定义中的最大值，必须保证 <code>VALUES LESS THAN</code> 中新定义的值大于现有分区中的所有值。否则，TiDB 将报错，提示现有的行值对应不到分区。</p><pre><code class="hljs language-sql"><div class="MuiBox-root css-1qhimia"><span class="hljs-keyword">INSERT</span> <span class="hljs-keyword">INTO</span> members <span class="hljs-keyword">VALUES</span> (<span class="hljs-number">313</span>, "John", "Doe", "2022-11-22", <span class="hljs-keyword">NULL</span>); <span class="hljs-keyword">ALTER</span> <span class="hljs-keyword">TABLE</span> members REORGANIZE <span class="hljs-keyword">PARTITION</span> p2000 <span class="hljs-keyword">INTO</span> (<span class="hljs-keyword">PARTITION</span> p2000 <span class="hljs-keyword">VALUES</span> LESS THAN (<span class="hljs-number">2050</span>)); <span class="hljs-comment">-- 执行成功，因为 2050 包含了现有的所有行</span> <span class="hljs-keyword">ALTER</span> <span class="hljs-keyword">TABLE</span> members REORGANIZE <span class="hljs-keyword">PARTITION</span> p2000 <span class="hljs-keyword">INTO</span> (<span class="hljs-keyword">PARTITION</span> p2000 <span class="hljs-keyword">VALUES</span> LESS THAN (<span class="hljs-number">2020</span>)); <span class="hljs-comment">-- 执行失败，因为 2022 将对应不到分区</span> </div><button class="MuiButtonBase-root MuiIconButton-root MuiIconButton-sizeSmall css-1rmx1rm" tabindex="0" type="button" aria-label="Toggle code wrap"><svg class="MuiSvgIcon-root MuiSvgIcon-fontSizeInherit css-1cw4hi4" focusable="false" aria-hidden="true" viewbox="0 0 24 24" data-testid="WrapTextIcon"><path d="M4 19h6v-2H4v2zM20 5H4v2h16V5zm-3 6H4v2h13.25c1.1 0 2 .9 2 2s-.9 2-2 2H15v-2l-3 3 3 3v-2h2c2.21 0 4-1.79 4-4s-1.79-4-4-4z"/></svg></button><button class="MuiButtonBase-root MuiIconButton-root MuiIconButton-sizeSmall css-fxo539" tabindex="0" type="button" aria-label="copy"><svg class="MuiSvgIcon-root MuiSvgIcon-fontSizeInherit css-1cw4hi4" focusable="false" aria-hidden="true" viewbox="0 0 24 24" data-testid="ContentCopyIcon"><path d="M16 1H4c-1.1 0-2 .9-2 2v14h2V3h12V1zm3 4H8c-1.1 0-2 .9-2 2v14c0 1.1.9 2 2 2h11c1.1 0 2-.9 2-2V7c0-1.1-.9-2-2-2zm0 16H8V7h11v14z"/></svg></button></code></pre><pre><code class="hljs language-"><div class="MuiBox-root css-1qhimia">ERROR 1526 (HY000): Table has no partition for value 2022 </div><button class="MuiButtonBase-root MuiIconButton-root MuiIconButton-sizeSmall css-1rmx1rm" tabindex="0" type="button" aria-label="Toggle code wrap"><svg class="MuiSvgIcon-root MuiSvgIcon-fontSizeInherit css-1cw4hi4" focusable="false" aria-hidden="true" viewbox="0 0 24 24" data-testid="WrapTextIcon"><path d="M4 19h6v-2H4v2zM20 5H4v2h16V5zm-3 6H4v2h13.25c1.1 0 2 .9 2 2s-.9 2-2 2H15v-2l-3 3 3 3v-2h2c2.21 0 4-1.79 4-4s-1.79-4-4-4z"/></svg></button><button class="MuiButtonBase-root MuiIconButton-root MuiIconButton-sizeSmall css-fxo539" tabindex="0" type="button" aria-label="copy"><svg class="MuiSvgIcon-root MuiSvgIcon-fontSizeInherit css-1cw4hi4" focusable="false" aria-hidden="true" viewbox="0 0 24 24" data-testid="ContentCopyIcon"><path d="M16 1H4c-1.1 0-2 .9-2 2v14h2V3h12V1zm3 4H8c-1.1 0-2 .9-2 2v14c0 1.1.9 2 2 2h11c1.1 0 2-.9 2-2V7c0-1.1-.9-2-2-2zm0 16H8V7h11v14z"/></svg></button></code></pre></li><li><p>对于 List 分区表，如需修改分区定义中的数据集合，必须保证新的数据集合能覆盖到该分区中现有的所有值，否则 TiDB 将报错。</p><pre><code class="hljs language-sql"><div class="MuiBox-root css-1qhimia"><span class="hljs-keyword">INSERT</span> <span class="hljs-keyword">INTO</span> member_level (id, level) <span class="hljs-keyword">values</span> (<span class="hljs-number">313</span>, <span class="hljs-number">6</span>); <span class="hljs-keyword">ALTER</span> <span class="hljs-keyword">TABLE</span> member_level REORGANIZE <span class="hljs-keyword">PARTITION</span> lEven <span class="hljs-keyword">INTO</span> (<span class="hljs-keyword">PARTITION</span> lEven <span class="hljs-keyword">VALUES</span> <span class="hljs-keyword">IN</span> (<span class="hljs-number">2</span>,<span class="hljs-number">4</span>)); </div><button class="MuiButtonBase-root MuiIconButton-root MuiIconButton-sizeSmall css-1rmx1rm" tabindex="0" type="button" aria-label="Toggle code wrap"><svg class="MuiSvgIcon-root MuiSvgIcon-fontSizeInherit css-1cw4hi4" focusable="false" aria-hidden="true" viewbox="0 0 24 24" data-testid="WrapTextIcon"><path d="M4 19h6v-2H4v2zM20 5H4v2h16V5zm-3 6H4v2h13.25c1.1 0 2 .9 2 2s-.9 2-2 2H15v-2l-3 3 3 3v-2h2c2.21 0 4-1.79 4-4s-1.79-4-4-4z"/></svg></button><button class="MuiButtonBase-root MuiIconButton-root MuiIconButton-sizeSmall css-fxo539" tabindex="0" type="button" aria-label="copy"><svg class="MuiSvgIcon-root MuiSvgIcon-fontSizeInherit css-1cw4hi4" focusable="false" aria-hidden="true" viewbox="0 0 24 24" data-testid="ContentCopyIcon"><path d="M16 1H4c-1.1 0-2 .9-2 2v14h2V3h12V1zm3 4H8c-1.1 0-2 .9-2 2v14c0 1.1.9 2 2 2h11c1.1 0 2-.9 2-2V7c0-1.1-.9-2-2-2zm0 16H8V7h11v14z"/></svg></button></code></pre><pre><code class="hljs language-"><div class="MuiBox-root css-1qhimia">ERROR 1526 (HY000): Table has no partition for value 6 </div><button class="MuiButtonBase-root MuiIconButton-root MuiIconButton-sizeSmall css-1rmx1rm" tabindex="0" type="button" aria-label="Toggle code wrap"><svg class="MuiSvgIcon-root MuiSvgIcon-fontSizeInherit css-1cw4hi4" focusable="false" aria-hidden="true" viewbox="0 0 24 24" data-testid="WrapTextIcon"><path d="M4 19h6v-2H4v2zM20 5H4v2h16V5zm-3 6H4v2h13.25c1.1 0 2 .9 2 2s-.9 2-2 2H15v-2l-3 3 3 3v-2h2c2.21 0 4-1.79 4-4s-1.79-4-4-4z"/></svg></button><button class="MuiButtonBase-root MuiIconButton-root MuiIconButton-sizeSmall css-fxo539" tabindex="0" type="button" aria-label="copy"><svg class="MuiSvgIcon-root MuiSvgIcon-fontSizeInherit css-1cw4hi4" focusable="false" aria-hidden="true" viewbox="0 0 24 24" data-testid="ContentCopyIcon"><path d="M16 1H4c-1.1 0-2 .9-2 2v14h2V3h12V1zm3 4H8c-1.1 0-2 .9-2 2v14c0 1.1.9 2 2 2h11c1.1 0 2-.9 2-2V7c0-1.1-.9-2-2-2zm0 16H8V7h11v14z"/></svg></button></code></pre></li><li><p>分区重组后，相应分区的统计信息将会过期，并返回以下警告。此时，你可以通过 [<code>ANALYZE TABLE</code>]（/sql-statements/sql-statement-analyze-table.md）语句更新统计信息。</p><pre><code class="hljs language-sql"><div class="MuiBox-root css-1qhimia"><span class="hljs-operator">+</span><span class="hljs-comment">---------+------+--------------------------------------------------------------------------------------------------------------------------------------------------------+</span> <span class="hljs-operator">|</span> Level <span class="hljs-operator">|</span> Code <span class="hljs-operator">|</span> Message <span class="hljs-operator">|</span> <span class="hljs-operator">+</span><span class="hljs-comment">---------+------+--------------------------------------------------------------------------------------------------------------------------------------------------------+</span> <span class="hljs-operator">|</span> Warning <span class="hljs-operator">|</span> <span class="hljs-number">1105</span> <span class="hljs-operator">|</span> The statistics <span class="hljs-keyword">of</span> related partitions will be outdated after reorganizing partitions. Please use <span class="hljs-string">'ANALYZE TABLE'</span> statement if you want <span class="hljs-keyword">to</span> <span class="hljs-keyword">update</span> it now <span class="hljs-operator">|</span> <span class="hljs-operator">+</span><span class="hljs-comment">---------+------+--------------------------------------------------------------------------------------------------------------------------------------------------------+</span> <span class="hljs-number">1</span> <span class="hljs-type">row</span> <span class="hljs-keyword">in</span> <span class="hljs-keyword">set</span> (<span class="hljs-number">0.00</span> sec) </div><button class="MuiButtonBase-root MuiIconButton-root MuiIconButton-sizeSmall css-1rmx1rm" tabindex="0" type="button" aria-label="Toggle code wrap"><svg class="MuiSvgIcon-root MuiSvgIcon-fontSizeInherit css-1cw4hi4" focusable="false" aria-hidden="true" viewbox="0 0 24 24" data-testid="WrapTextIcon"><path d="M4 19h6v-2H4v2zM20 5H4v2h16V5zm-3 6H4v2h13.25c1.1 0 2 .9 2 2s-.9 2-2 2H15v-2l-3 3 3 3v-2h2c2.21 0 4-1.79 4-4s-1.79-4-4-4z"/></svg></button><button class="MuiButtonBase-root MuiIconButton-root MuiIconButton-sizeSmall css-fxo539" tabindex="0" type="button" aria-label="copy"><svg class="MuiSvgIcon-root MuiSvgIcon-fontSizeInherit css-1cw4hi4" focusable="false" aria-hidden="true" viewbox="0 0 24 24" data-testid="ContentCopyIcon"><path d="M16 1H4c-1.1 0-2 .9-2 2v14h2V3h12V1zm3 4H8c-1.1 0-2 .9-2 2v14c0 1.1.9 2 2 2h11c1.1 0 2-.9 2-2V7c0-1.1-.9-2-2-2zm0 16H8V7h11v14z"/></svg></button></code></pre></li></ul><h3 id="管理-hash-分区和-key-分区" style="position:relative"><a href="#%E7%AE%A1%E7%90%86-hash-%E5%88%86%E5%8C%BA%E5%92%8C-key-%E5%88%86%E5%8C%BA" aria-label="管理 hash 分区和 key 分区 permalink" class="anchor before"><svg aria-hidden="true" focusable="false" height="16" version="1.1" viewbox="0 0 16 16" width="16"><path fill-rule="evenodd" d="M4 9h1v1H4c-1.5 0-3-1.69-3-3.5S2.55 3 4 3h4c1.45 0 3 1.69 3 3.5 0 1.41-.91 2.72-2 3.25V8.59c.58-.45 1-1.27 1-2.09C10 5.22 8.98 4 8 4H4c-.98 0-2 1.22-2 2.5S3 9 4 9zm9-3h-1v1h1c1 0 2 1.22 2 2.5S13.98 12 13 12H9c-.98 0-2-1.22-2-2.5 0-.83.42-1.64 1-2.09V6.25c-1.09.53-2 1.84-2 3.25C6 11.31 7.55 13 9 13h4c1.45 0 3-1.69 3-3.5S14.5 6 13 6z"/></svg></a>管理 Hash 分区和 Key 分区</h3><p>本小节将以如下 SQL 语句创建的分区表为例，介绍如何管理 Hash 分区。对于 Key 分区，你也可以使用与 Hash 分区相同的分区管理语句。</p><pre><code class="hljs language-sql"><div class="MuiBox-root css-1qhimia"><span class="hljs-keyword">CREATE</span> <span class="hljs-keyword">TABLE</span> example ( id <span class="hljs-type">INT</span> <span class="hljs-keyword">PRIMARY</span> KEY, data <span class="hljs-type">VARCHAR</span>(<span class="hljs-number">1024</span>) <span class="hljs-keyword">PARTITION</span> <span class="hljs-keyword">BY</span> HASH(id) PARTITIONS <span class="hljs-number">2</span>; </div><button class="MuiButtonBase-root MuiIconButton-root MuiIconButton-sizeSmall css-1rmx1rm" tabindex="0" type="button" aria-label="Toggle code wrap"><svg class="MuiSvgIcon-root MuiSvgIcon-fontSizeInherit css-1cw4hi4" focusable="false" aria-hidden="true" viewbox="0 0 24 24" data-testid="WrapTextIcon"><path d="M4 19h6v-2H4v2zM20 5H4v2h16V5zm-3 6H4v2h13.25c1.1 0 2 .9 2 2s-.9 2-2 2H15v-2l-3 3 3 3v-2h2c2.21 0 4-1.79 4-4s-1.79-4-4-4z"/></svg></button><button class="MuiButtonBase-root MuiIconButton-root MuiIconButton-sizeSmall css-fxo539" tabindex="0" type="button" aria-label="copy"><svg class="MuiSvgIcon-root MuiSvgIcon-fontSizeInherit css-1cw4hi4" focusable="false" aria-hidden="true" viewbox="0 0 24 24" data-testid="ContentCopyIcon"><path d="M16 1H4c-1.1 0-2 .9-2 2v14h2V3h12V1zm3 4H8c-1.1 0-2 .9-2 2v14c0 1.1.9 2 2 2h11c1.1 0 2-.9 2-2V7c0-1.1-.9-2-2-2zm0 16H8V7h11v14z"/></svg></button></code></pre><h4 id="增加分区数量" style="position:relative"><a href="#%E5%A2%9E%E5%8A%A0%E5%88%86%E5%8C%BA%E6%95%B0%E9%87%8F" aria-label="增加分区数量 permalink" class="anchor before"><svg aria-hidden="true" focusable="false" height="16" version="1.1" viewbox="0 0 16 16" width="16"><path fill-rule="evenodd" d="M4 9h1v1H4c-1.5 0-3-1.69-3-3.5S2.55 3 4 3h4c1.45 0 3 1.69 3 3.5 0 1.41-.91 2.72-2 3.25V8.59c.58-.45 1-1.27 1-2.09C10 5.22 8.98 4 8 4H4c-.98 0-2 1.22-2 2.5S3 9 4 9zm9-3h-1v1h1c1 0 2 1.22 2 2.5S13.98 12 13 12H9c-.98 0-2-1.22-2-2.5 0-.83.42-1.64 1-2.09V6.25c-1.09.53-2 1.84-2 3.25C6 11.31 7.55 13 9 13h4c1.45 0 3-1.69 3-3.5S14.5 6 13 6z"/></svg></a>增加分区数量</h4><p>将 <code>example</code> 表的分区个数增加 1 个（从 2 增加到 3）：</p><pre><code class="hljs language-sql"><div class="MuiBox-root css-1qhimia"><span class="hljs-keyword">ALTER</span> <span class="hljs-keyword">TABLE</span> example <span class="hljs-keyword">ADD</span> <span class="hljs-keyword">PARTITION</span> PARTITIONS <span class="hljs-number">1</span>; </div><button class="MuiButtonBase-root MuiIconButton-root MuiIconButton-sizeSmall css-1rmx1rm" tabindex="0" type="button" aria-label="Toggle code wrap"><svg class="MuiSvgIcon-root MuiSvgIcon-fontSizeInherit css-1cw4hi4" focusable="false" aria-hidden="true" viewbox="0 0 24 24" data-testid="WrapTextIcon"><path d="M4 19h6v-2H4v2zM20 5H4v2h16V5zm-3 6H4v2h13.25c1.1 0 2 .9 2 2s-.9 2-2 2H15v-2l-3 3 3 3v-2h2c2.21 0 4-1.79 4-4s-1.79-4-4-4z"/></svg></button><button class="MuiButtonBase-root MuiIconButton-root MuiIconButton-sizeSmall css-fxo539" tabindex="0" type="button" aria-label="copy"><svg class="MuiSvgIcon-root MuiSvgIcon-fontSizeInherit css-1cw4hi4" focusable="false" aria-hidden="true" viewbox="0 0 24 24" data-testid="ContentCopyIcon"><path d="M16 1H4c-1.1 0-2 .9-2 2v14h2V3h12V1zm3 4H8c-1.1 0-2 .9-2 2v14c0 1.1.9 2 2 2h11c1.1 0 2-.9 2-2V7c0-1.1-.9-2-2-2zm0 16H8V7h11v14z"/></svg></button></code></pre><p>你也可以通过添加分区定义来指定分区选项。例如，你可以通过以下语句将分区数量从 3 增加到 5，并指定新增的分区名为 <code>pExample4</code> 和 <code>pExample5</code>：</p><pre><code class="hljs language-sql"><div class="MuiBox-root css-1qhimia"><span class="hljs-keyword">ALTER</span> <span class="hljs-keyword">TABLE</span> example <span class="hljs-keyword">ADD</span> <span class="hljs-keyword">PARTITION</span> (<span class="hljs-keyword">PARTITION</span> pExample4 COMMENT <span class="hljs-operator">=</span> <span class="hljs-string">'not p3, but pExample4 instead'</span>, <span class="hljs-keyword">PARTITION</span> pExample5 COMMENT <span class="hljs-operator">=</span> <span class="hljs-string">'not p4, but pExample5 instead'</span>); </div><button class="MuiButtonBase-root MuiIconButton-root MuiIconButton-sizeSmall css-1rmx1rm" tabindex="0" type="button" aria-label="Toggle code wrap"><svg class="MuiSvgIcon-root MuiSvgIcon-fontSizeInherit css-1cw4hi4" focusable="false" aria-hidden="true" viewbox="0 0 24 24" data-testid="WrapTextIcon"><path d="M4 19h6v-2H4v2zM20 5H4v2h16V5zm-3 6H4v2h13.25c1.1 0 2 .9 2 2s-.9 2-2 2H15v-2l-3 3 3 3v-2h2c2.21 0 4-1.79 4-4s-1.79-4-4-4z"/></svg></button><button class="MuiButtonBase-root MuiIconButton-root MuiIconButton-sizeSmall css-fxo539" tabindex="0" type="button" aria-label="copy"><svg class="MuiSvgIcon-root MuiSvgIcon-fontSizeInherit css-1cw4hi4" focusable="false" aria-hidden="true" viewbox="0 0 24 24" data-testid="ContentCopyIcon"><path d="M16 1H4c-1.1 0-2 .9-2 2v14h2V3h12V1zm3 4H8c-1.1 0-2 .9-2 2v14c0 1.1.9 2 2 2h11c1.1 0 2-.9 2-2V7c0-1.1-.9-2-2-2zm0 16H8V7h11v14z"/></svg></button></code></pre><h4 id="减少分区数量" style="position:relative"><a href="#%E5%87%8F%E5%B0%91%E5%88%86%E5%8C%BA%E6%95%B0%E9%87%8F" aria-label="减少分区数量 permalink" class="anchor before"><svg aria-hidden="true" focusable="false" height="16" version="1.1" viewbox="0 0 16 16" width="16"><path fill-rule="evenodd" d="M4 9h1v1H4c-1.5 0-3-1.69-3-3.5S2.55 3 4 3h4c1.45 0 3 1.69 3 3.5 0 1.41-.91 2.72-2 3.25V8.59c.58-.45 1-1.27 1-2.09C10 5.22 8.98 4 8 4H4c-.98 0-2 1.22-2 2.5S3 9 4 9zm9-3h-1v1h1c1 0 2 1.22 2 2.5S13.98 12 13 12H9c-.98 0-2-1.22-2-2.5 0-.83.42-1.64 1-2.09V6.25c-1.09.53-2 1.84-2 3.25C6 11.31 7.55 13 9 13h4c1.45 0 3-1.69 3-3.5S14.5 6 13 6z"/></svg></a>减少分区数量</h4><p>与 Range 和 List 分区不同，Hash 和 Key 分区不支持 <code>DROP PARTITION</code>，但可以使用 <code>COALESCE PARTITION</code> 来减少分区数量，或使用 <code>TRUNCATE PARTITION</code> 清空指定分区的所有数据。</p><p>将 <code>example</code> 表的分区个数减少 1 个（从 5 减少到 4）：</p><pre><code class="hljs language-sql"><div class="MuiBox-root css-1qhimia"><span class="hljs-keyword">ALTER</span> <span class="hljs-keyword">TABLE</span> example COALESCE <span class="hljs-keyword">PARTITION</span> <span class="hljs-number">1</span>; </div><button class="MuiButtonBase-root MuiIconButton-root MuiIconButton-sizeSmall css-1rmx1rm" tabindex="0" type="button" aria-label="Toggle code wrap"><svg class="MuiSvgIcon-root MuiSvgIcon-fontSizeInherit css-1cw4hi4" focusable="false" aria-hidden="true" viewbox="0 0 24 24" data-testid="WrapTextIcon"><path d="M4 19h6v-2H4v2zM20 5H4v2h16V5zm-3 6H4v2h13.25c1.1 0 2 .9 2 2s-.9 2-2 2H15v-2l-3 3 3 3v-2h2c2.21 0 4-1.79 4-4s-1.79-4-4-4z"/></svg></button><button class="MuiButtonBase-root MuiIconButton-root MuiIconButton-sizeSmall css-fxo539" tabindex="0" type="button" aria-label="copy"><svg class="MuiSvgIcon-root MuiSvgIcon-fontSizeInherit css-1cw4hi4" focusable="false" aria-hidden="true" viewbox="0 0 24 24" data-testid="ContentCopyIcon"><path d="M16 1H4c-1.1 0-2 .9-2 2v14h2V3h12V1zm3 4H8c-1.1 0-2 .9-2 2v14c0 1.1.9 2 2 2h11c1.1 0 2-.9 2-2V7c0-1.1-.9-2-2-2zm0 16H8V7h11v14z"/></svg></button></code></pre><div class="MuiBox-root css-1weqspv"><div class="MuiPaper-root MuiPaper-elevation MuiPaper-rounded MuiPaper-elevation0 MuiAlert-root MuiAlert-standardInfo MuiAlert-standard css-152gid5" role="alert"><div class="MuiAlert-icon css-1l54tgj"><svg class="MuiSvgIcon-root MuiSvgIcon-fontSizeInherit css-1cw4hi4" focusable="false" aria-hidden="true" viewbox="0 0 24 24" data-testid="InfoOutlinedIcon"><path d="M11,9H13V7H11M12,20C7.59,20 4,16.41 4,12C4,7.59 7.59,4 12,4C16.41,4 20,7.59 20, 12C20,16.41 16.41,20 12,20M12,2A10,10 0 0,0 2,12A10,10 0 0,0 12,22A10,10 0 0,0 22,12A10, 10 0 0,0 12,2M11,17H13V11H11V17Z"/></svg></div><div class="MuiAlert-message css-1xsto0d"><div class="MuiTypography-root MuiTypography-body1 MuiTypography-gutterBottom MuiAlertTitle-root css-17ioyuk">注意</div><p>更改 Hash 和 Key 分区表的分区个数的过程会重组分区，将所有数据按照新的分区个数复制到对应的分区。因此，更改 Hash 和 Key 分区表的分区个数后，会遇到以下关于过时统计信息的警告。此时，你可以通过 <a href="/zh/tidb/stable/sql-statement-analyze-table"><code>ANALYZE TABLE</code></a> 语句更新统计信息。</p><pre><code class="hljs language-sql"><div class="MuiBox-root css-1qhimia"><span class="hljs-operator">+</span><span class="hljs-comment">---------+------+--------------------------------------------------------------------------------------------------------------------------------------------------------+</span> <span class="hljs-operator">|</span> Level <span class="hljs-operator">|</span> Code <span class="hljs-operator">|</span> Message <span class="hljs-operator">|</span> <span class="hljs-operator">+</span><span class="hljs-comment">---------+------+--------------------------------------------------------------------------------------------------------------------------------------------------------+</span> <span class="hljs-operator">|</span> Warning <span class="hljs-operator">|</span> <span class="hljs-number">1105</span> <span class="hljs-operator">|</span> The statistics <span class="hljs-keyword">of</span> related partitions will be outdated after reorganizing partitions. Please use <span class="hljs-string">'ANALYZE TABLE'</span> statement if you want <span class="hljs-keyword">to</span> <span class="hljs-keyword">update</span> it now <span class="hljs-operator">|</span> <span class="hljs-operator">+</span><span class="hljs-comment">---------+------+--------------------------------------------------------------------------------------------------------------------------------------------------------+</span> <span class="hljs-number">1</span> <span class="hljs-type">row</span> <span class="hljs-keyword">in</span> <span class="hljs-keyword">set</span> (<span class="hljs-number">0.00</span> sec) </div><button class="MuiButtonBase-root MuiIconButton-root MuiIconButton-sizeSmall css-1rmx1rm" tabindex="0" type="button" aria-label="Toggle code wrap"><svg class="MuiSvgIcon-root MuiSvgIcon-fontSizeInherit css-1cw4hi4" focusable="false" aria-hidden="true" viewbox="0 0 24 24" data-testid="WrapTextIcon"><path d="M4 19h6v-2H4v2zM20 5H4v2h16V5zm-3 6H4v2h13.25c1.1 0 2 .9 2 2s-.9 2-2 2H15v-2l-3 3 3 3v-2h2c2.21 0 4-1.79 4-4s-1.79-4-4-4z"/></svg></button><button class="MuiButtonBase-root MuiIconButton-root MuiIconButton-sizeSmall css-fxo539" tabindex="0" type="button" aria-label="copy"><svg class="MuiSvgIcon-root MuiSvgIcon-fontSizeInherit css-1cw4hi4" focusable="false" aria-hidden="true" viewbox="0 0 24 24" data-testid="ContentCopyIcon"><path d="M16 1H4c-1.1 0-2 .9-2 2v14h2V3h12V1zm3 4H8c-1.1 0-2 .9-2 2v14c0 1.1.9 2 2 2h11c1.1 0 2-.9 2-2V7c0-1.1-.9-2-2-2zm0 16H8V7h11v14z"/></svg></button></code></pre></div></div></div><p>为了更好地理解 <code>example</code> 表重组后的结构，你可以查看重新创建 <code>example</code> 表所使用的 SQL 语句，如下所示：</p><pre><code class="hljs language-sql"><div class="MuiBox-root css-1qhimia"><span class="hljs-keyword">SHOW</span> <span class="hljs-keyword">CREATE</span> <span class="hljs-keyword">TABLE</span>\G </div><button class="MuiButtonBase-root MuiIconButton-root MuiIconButton-sizeSmall css-1rmx1rm" tabindex="0" type="button" aria-label="Toggle code wrap"><svg class="MuiSvgIcon-root MuiSvgIcon-fontSizeInherit css-1cw4hi4" focusable="false" aria-hidden="true" viewbox="0 0 24 24" data-testid="WrapTextIcon"><path d="M4 19h6v-2H4v2zM20 5H4v2h16V5zm-3 6H4v2h13.25c1.1 0 2 .9 2 2s-.9 2-2 2H15v-2l-3 3 3 3v-2h2c2.21 0 4-1.79 4-4s-1.79-4-4-4z"/></svg></button><button class="MuiButtonBase-root MuiIconButton-root MuiIconButton-sizeSmall css-fxo539" tabindex="0" type="button" aria-label="copy"><svg class="MuiSvgIcon-root MuiSvgIcon-fontSizeInherit css-1cw4hi4" focusable="false" aria-hidden="true" viewbox="0 0 24 24" data-testid="ContentCopyIcon"><path d="M16 1H4c-1.1 0-2 .9-2 2v14h2V3h12V1zm3 4H8c-1.1 0-2 .9-2 2v14c0 1.1.9 2 2 2h11c1.1 0 2-.9 2-2V7c0-1.1-.9-2-2-2zm0 16H8V7h11v14z"/></svg></button></code></pre><pre><code class="hljs language-"><div class="MuiBox-root css-1qhimia">*************************** 1. row *************************** Table: example Create Table: CREATE TABLE `example` ( `id` int(11) NOT NULL, `data` varchar(1024) DEFAULT NULL, PRIMARY KEY (`id`) /*T![clustered_index] CLUSTERED */ ) ENGINE=InnoDB DEFAULT CHARSET=utf8mb4 COLLATE=utf8mb4_bin PARTITION BY HASH (`id`) (PARTITION `p0`, PARTITION `p1`, PARTITION `p2`, PARTITION `pExample4` COMMENT 'not p3, but pExample4 instead') 1 row in set (0.01 sec) </div><button class="MuiButtonBase-root MuiIconButton-root MuiIconButton-sizeSmall css-1rmx1rm" tabindex="0" type="button" aria-label="Toggle code wrap"><svg class="MuiSvgIcon-root MuiSvgIcon-fontSizeInherit css-1cw4hi4" focusable="false" aria-hidden="true" viewbox="0 0 24 24" data-testid="WrapTextIcon"><path d="M4 19h6v-2H4v2zM20 5H4v2h16V5zm-3 6H4v2h13.25c1.1 0 2 .9 2 2s-.9 2-2 2H15v-2l-3 3 3 3v-2h2c2.21 0 4-1.79 4-4s-1.79-4-4-4z"/></svg></button><button class="MuiButtonBase-root MuiIconButton-root MuiIconButton-sizeSmall css-fxo539" tabindex="0" type="button" aria-label="copy"><svg class="MuiSvgIcon-root MuiSvgIcon-fontSizeInherit css-1cw4hi4" focusable="false" aria-hidden="true" viewbox="0 0 24 24" data-testid="ContentCopyIcon"><path d="M16 1H4c-1.1 0-2 .9-2 2v14h2V3h12V1zm3 4H8c-1.1 0-2 .9-2 2v14c0 1.1.9 2 2 2h11c1.1 0 2-.9 2-2V7c0-1.1-.9-2-2-2zm0 16H8V7h11v14z"/></svg></button></code></pre><h4 id="清空分区-1" style="position:relative"><a href="#%E6%B8%85%E7%A9%BA%E5%88%86%E5%8C%BA-1" aria-label="清空分区 1 permalink" class="anchor before"><svg aria-hidden="true" focusable="false" height="16" version="1.1" viewbox="0 0 16 16" width="16"><path fill-rule="evenodd" d="M4 9h1v1H4c-1.5 0-3-1.69-3-3.5S2.55 3 4 3h4c1.45 0 3 1.69 3 3.5 0 1.41-.91 2.72-2 3.25V8.59c.58-.45 1-1.27 1-2.09C10 5.22 8.98 4 8 4H4c-.98 0-2 1.22-2 2.5S3 9 4 9zm9-3h-1v1h1c1 0 2 1.22 2 2.5S13.98 12 13 12H9c-.98 0-2-1.22-2-2.5 0-.83.42-1.64 1-2.09V6.25c-1.09.53-2 1.84-2 3.25C6 11.31 7.55 13 9 13h4c1.45 0 3-1.69 3-3.5S14.5 6 13 6z"/></svg></a>清空分区</h4><p>清空指定分区的所有数据：</p><pre><code class="hljs language-sql"><div class="MuiBox-root css-1qhimia"><span class="hljs-keyword">ALTER</span> <span class="hljs-keyword">TABLE</span> example <span class="hljs-keyword">TRUNCATE</span> <span class="hljs-keyword">PARTITION</span> p0; </div><button class="MuiButtonBase-root MuiIconButton-root MuiIconButton-sizeSmall css-1rmx1rm" tabindex="0" type="button" aria-label="Toggle code wrap"><svg class="MuiSvgIcon-root MuiSvgIcon-fontSizeInherit css-1cw4hi4" focusable="false" aria-hidden="true" viewbox="0 0 24 24" data-testid="WrapTextIcon"><path d="M4 19h6v-2H4v2zM20 5H4v2h16V5zm-3 6H4v2h13.25c1.1 0 2 .9 2 2s-.9 2-2 2H15v-2l-3 3 3 3v-2h2c2.21 0 4-1.79 4-4s-1.79-4-4-4z"/></svg></button><button class="MuiButtonBase-root MuiIconButton-root MuiIconButton-sizeSmall css-fxo539" tabindex="0" type="button" aria-label="copy"><svg class="MuiSvgIcon-root MuiSvgIcon-fontSizeInherit css-1cw4hi4" focusable="false" aria-hidden="true" viewbox="0 0 24 24" data-testid="ContentCopyIcon"><path d="M16 1H4c-1.1 0-2 .9-2 2v14h2V3h12V1zm3 4H8c-1.1 0-2 .9-2 2v14c0 1.1.9 2 2 2h11c1.1 0 2-.9 2-2V7c0-1.1-.9-2-2-2zm0 16H8V7h11v14z"/></svg></button></code></pre><pre><code class="hljs language-"><div class="MuiBox-root css-1qhimia">Query OK, 0 rows affected (0.03 sec) </div><button class="MuiButtonBase-root MuiIconButton-root MuiIconButton-sizeSmall css-1rmx1rm" tabindex="0" type="button" aria-label="Toggle code wrap"><svg class="MuiSvgIcon-root MuiSvgIcon-fontSizeInherit css-1cw4hi4" focusable="false" aria-hidden="true" viewbox="0 0 24 24" data-testid="WrapTextIcon"><path d="M4 19h6v-2H4v2zM20 5H4v2h16V5zm-3 6H4v2h13.25c1.1 0 2 .9 2 2s-.9 2-2 2H15v-2l-3 3 3 3v-2h2c2.21 0 4-1.79 4-4s-1.79-4-4-4z"/></svg></button><button class="MuiButtonBase-root MuiIconButton-root MuiIconButton-sizeSmall css-fxo539" tabindex="0" type="button" aria-label="copy"><svg class="MuiSvgIcon-root MuiSvgIcon-fontSizeInherit css-1cw4hi4" focusable="false" aria-hidden="true" viewbox="0 0 24 24" data-testid="ContentCopyIcon"><path d="M16 1H4c-1.1 0-2 .9-2 2v14h2V3h12V1zm3 4H8c-1.1 0-2 .9-2 2v14c0 1.1.9 2 2 2h11c1.1 0 2-.9 2-2V7c0-1.1-.9-2-2-2zm0 16H8V7h11v14z"/></svg></button></code></pre><h3 id="将分区表转换为非分区表" style="position:relative"><a href="#%E5%B0%86%E5%88%86%E5%8C%BA%E8%A1%A8%E8%BD%AC%E6%8D%A2%E4%B8%BA%E9%9D%9E%E5%88%86%E5%8C%BA%E8%A1%A8" aria-label="将分区表转换为非分区表 permalink" class="anchor before"><svg aria-hidden="true" focusable="false" height="16" version="1.1" viewbox="0 0 16 16" width="16"><path fill-rule="evenodd" d="M4 9h1v1H4c-1.5 0-3-1.69-3-3.5S2.55 3 4 3h4c1.45 0 3 1.69 3 3.5 0 1.41-.91 2.72-2 3.25V8.59c.58-.45 1-1.27 1-2.09C10 5.22 8.98 4 8 4H4c-.98 0-2 1.22-2 2.5S3 9 4 9zm9-3h-1v1h1c1 0 2 1.22 2 2.5S13.98 12 13 12H9c-.98 0-2-1.22-2-2.5 0-.83.42-1.64 1-2.09V6.25c-1.09.53-2 1.84-2 3.25C6 11.31 7.55 13 9 13h4c1.45 0 3-1.69 3-3.5S14.5 6 13 6z"/></svg></a>将分区表转换为非分区表</h3><p>要将分区表转换为非分区表，你可以使用以下语句。该语句在执行时将会删除分区，复制表中的所有行，并为表在线重新创建索引。</p><pre><code class="hljs language-sql"><div class="MuiBox-root css-1qhimia"><span class="hljs-keyword">ALTER</span> <span class="hljs-keyword">TABLE</span> <span class="hljs-operator">&lt;</span>table_name<span class="hljs-operator">&gt;</span> REMOVE PARTITIONING </div><button class="MuiButtonBase-root MuiIconButton-root MuiIconButton-sizeSmall css-1rmx1rm" tabindex="0" type="button" aria-label="Toggle code wrap"><svg class="MuiSvgIcon-root MuiSvgIcon-fontSizeInherit css-1cw4hi4" focusable="false" aria-hidden="true" viewbox="0 0 24 24" data-testid="WrapTextIcon"><path d="M4 19h6v-2H4v2zM20 5H4v2h16V5zm-3 6H4v2h13.25c1.1 0 2 .9 2 2s-.9 2-2 2H15v-2l-3 3 3 3v-2h2c2.21 0 4-1.79 4-4s-1.79-4-4-4z"/></svg></button><button class="MuiButtonBase-root MuiIconButton-root MuiIconButton-sizeSmall css-fxo539" tabindex="0" type="button" aria-label="copy"><svg class="MuiSvgIcon-root MuiSvgIcon-fontSizeInherit css-1cw4hi4" focusable="false" aria-hidden="true" viewbox="0 0 24 24" data-testid="ContentCopyIcon"><path d="M16 1H4c-1.1 0-2 .9-2 2v14h2V3h12V1zm3 4H8c-1.1 0-2 .9-2 2v14c0 1.1.9 2 2 2h11c1.1 0 2-.9 2-2V7c0-1.1-.9-2-2-2zm0 16H8V7h11v14z"/></svg></button></code></pre><p>例如，要将分区表 <code>members</code> 转换为非分区表，可以执行以下语句：</p><pre><code class="hljs language-sql"><div class="MuiBox-root css-1qhimia"><span class="hljs-keyword">ALTER</span> <span class="hljs-keyword">TABLE</span> members REMOVE PARTITIONING </div><button class="MuiButtonBase-root MuiIconButton-root MuiIconButton-sizeSmall css-1rmx1rm" tabindex="0" type="button" aria-label="Toggle code wrap"><svg class="MuiSvgIcon-root MuiSvgIcon-fontSizeInherit css-1cw4hi4" focusable="false" aria-hidden="true" viewbox="0 0 24 24" data-testid="WrapTextIcon"><path d="M4 19h6v-2H4v2zM20 5H4v2h16V5zm-3 6H4v2h13.25c1.1 0 2 .9 2 2s-.9 2-2 2H15v-2l-3 3 3 3v-2h2c2.21 0 4-1.79 4-4s-1.79-4-4-4z"/></svg></button><button class="MuiButtonBase-root MuiIconButton-root MuiIconButton-sizeSmall css-fxo539" tabindex="0" type="button" aria-label="copy"><svg class="MuiSvgIcon-root MuiSvgIcon-fontSizeInherit css-1cw4hi4" focusable="false" aria-hidden="true" viewbox="0 0 24 24" data-testid="ContentCopyIcon"><path d="M16 1H4c-1.1 0-2 .9-2 2v14h2V3h12V1zm3 4H8c-1.1 0-2 .9-2 2v14c0 1.1.9 2 2 2h11c1.1 0 2-.9 2-2V7c0-1.1-.9-2-2-2zm0 16H8V7h11v14z"/></svg></button></code></pre><h3 id="对现有表进行分区" style="position:relative"><a href="#%E5%AF%B9%E7%8E%B0%E6%9C%89%E8%A1%A8%E8%BF%9B%E8%A1%8C%E5%88%86%E5%8C%BA" aria-label="对现有表进行分区 permalink" class="anchor before"><svg aria-hidden="true" focusable="false" height="16" version="1.1" viewbox="0 0 16 16" width="16"><path fill-rule="evenodd" d="M4 9h1v1H4c-1.5 0-3-1.69-3-3.5S2.55 3 4 3h4c1.45 0 3 1.69 3 3.5 0 1.41-.91 2.72-2 3.25V8.59c.58-.45 1-1.27 1-2.09C10 5.22 8.98 4 8 4H4c-.98 0-2 1.22-2 2.5S3 9 4 9zm9-3h-1v1h1c1 0 2 1.22 2 2.5S13.98 12 13 12H9c-.98 0-2-1.22-2-2.5 0-.83.42-1.64 1-2.09V6.25c-1.09.53-2 1.84-2 3.25C6 11.31 7.55 13 9 13h4c1.45 0 3-1.69 3-3.5S14.5 6 13 6z"/></svg></a>对现有表进行分区</h3><p>要对现有的非分区表进行分区或修改现有分区表的分区类型，你可以使用以下语句。该语句在执行时，将根据新的分区定义复制表中的所有行，并在线重新创建索引：</p><pre><code class="hljs language-sql"><div class="MuiBox-root css-1qhimia"><span class="hljs-keyword">ALTER</span> <span class="hljs-keyword">TABLE</span> <span class="hljs-operator">&lt;</span>table_name<span class="hljs-operator">&gt;</span> <span class="hljs-keyword">PARTITION</span> <span class="hljs-keyword">BY</span> <span class="hljs-operator">&lt;</span><span class="hljs-keyword">new</span> <span class="hljs-keyword">partition</span> type <span class="hljs-keyword">and</span> definitions<span class="hljs-operator">&gt;</span> </div><button class="MuiButtonBase-root MuiIconButton-root MuiIconButton-sizeSmall css-1rmx1rm" tabindex="0" type="button" aria-label="Toggle code wrap"><svg class="MuiSvgIcon-root MuiSvgIcon-fontSizeInherit css-1cw4hi4" focusable="false" aria-hidden="true" viewbox="0 0 24 24" data-testid="WrapTextIcon"><path d="M4 19h6v-2H4v2zM20 5H4v2h16V5zm-3 6H4v2h13.25c1.1 0 2 .9 2 2s-.9 2-2 2H15v-2l-3 3 3 3v-2h2c2.21 0 4-1.79 4-4s-1.79-4-4-4z"/></svg></button><button class="MuiButtonBase-root MuiIconButton-root MuiIconButton-sizeSmall css-fxo539" tabindex="0" type="button" aria-label="copy"><svg class="MuiSvgIcon-root MuiSvgIcon-fontSizeInherit css-1cw4hi4" focusable="false" aria-hidden="true" viewbox="0 0 24 24" data-testid="ContentCopyIcon"><path d="M16 1H4c-1.1 0-2 .9-2 2v14h2V3h12V1zm3 4H8c-1.1 0-2 .9-2 2v14c0 1.1.9 2 2 2h11c1.1 0 2-.9 2-2V7c0-1.1-.9-2-2-2zm0 16H8V7h11v14z"/></svg></button></code></pre><p>示例：</p><p>要将现有的 <code>members</code> 表转换为一个包含 10 个分区的 HASH 分区表，可以执行以下语句：</p><pre><code class="hljs language-sql"><div class="MuiBox-root css-1qhimia"><span class="hljs-keyword">ALTER</span> <span class="hljs-keyword">TABLE</span> members <span class="hljs-keyword">PARTITION</span> <span class="hljs-keyword">BY</span> HASH(id) PARTITIONS <span class="hljs-number">10</span>; </div><button class="MuiButtonBase-root MuiIconButton-root MuiIconButton-sizeSmall css-1rmx1rm" tabindex="0" type="button" aria-label="Toggle code wrap"><svg class="MuiSvgIcon-root MuiSvgIcon-fontSizeInherit css-1cw4hi4" focusable="false" aria-hidden="true" viewbox="0 0 24 24" data-testid="WrapTextIcon"><path d="M4 19h6v-2H4v2zM20 5H4v2h16V5zm-3 6H4v2h13.25c1.1 0 2 .9 2 2s-.9 2-2 2H15v-2l-3 3 3 3v-2h2c2.21 0 4-1.79 4-4s-1.79-4-4-4z"/></svg></button><button class="MuiButtonBase-root MuiIconButton-root MuiIconButton-sizeSmall css-fxo539" tabindex="0" type="button" aria-label="copy"><svg class="MuiSvgIcon-root MuiSvgIcon-fontSizeInherit css-1cw4hi4" focusable="false" aria-hidden="true" viewbox="0 0 24 24" data-testid="ContentCopyIcon"><path d="M16 1H4c-1.1 0-2 .9-2 2v14h2V3h12V1zm3 4H8c-1.1 0-2 .9-2 2v14c0 1.1.9 2 2 2h11c1.1 0 2-.9 2-2V7c0-1.1-.9-2-2-2zm0 16H8V7h11v14z"/></svg></button></code></pre><p>要将现有的 <code>member_level</code> 表转换为 RANGE 分区表，可以执行以下语句：</p><pre><code class="hljs language-sql"><div class="MuiBox-root css-1qhimia"><span class="hljs-keyword">ALTER</span> <span class="hljs-keyword">TABLE</span> member_level <span class="hljs-keyword">PARTITION</span> <span class="hljs-keyword">BY</span> <span class="hljs-keyword">RANGE</span>(level) (<span class="hljs-keyword">PARTITION</span> pLow <span class="hljs-keyword">VALUES</span> LESS THAN (<span class="hljs-number">1</span>), <span class="hljs-keyword">PARTITION</span> pMid <span class="hljs-keyword">VALUES</span> LESS THAN (<span class="hljs-number">3</span>), <span class="hljs-keyword">PARTITION</span> pHigh <span class="hljs-keyword">VALUES</span> LESS THAN (<span class="hljs-number">7</span>) <span class="hljs-keyword">PARTITION</span> pMax <span class="hljs-keyword">VALUES</span> LESS THAN (MAXVALUE)); </div><button class="MuiButtonBase-root MuiIconButton-root MuiIconButton-sizeSmall css-1rmx1rm" tabindex="0" type="button" aria-label="Toggle code wrap"><svg class="MuiSvgIcon-root MuiSvgIcon-fontSizeInherit css-1cw4hi4" focusable="false" aria-hidden="true" viewbox="0 0 24 24" data-testid="WrapTextIcon"><path d="M4 19h6v-2H4v2zM20 5H4v2h16V5zm-3 6H4v2h13.25c1.1 0 2 .9 2 2s-.9 2-2 2H15v-2l-3 3 3 3v-2h2c2.21 0 4-1.79 4-4s-1.79-4-4-4z"/></svg></button><button class="MuiButtonBase-root MuiIconButton-root MuiIconButton-sizeSmall css-fxo539" tabindex="0" type="button" aria-label="copy"><svg class="MuiSvgIcon-root MuiSvgIcon-fontSizeInherit css-1cw4hi4" focusable="false" aria-hidden="true" viewbox="0 0 24 24" data-testid="ContentCopyIcon"><path d="M16 1H4c-1.1 0-2 .9-2 2v14h2V3h12V1zm3 4H8c-1.1 0-2 .9-2 2v14c0 1.1.9 2 2 2h11c1.1 0 2-.9 2-2V7c0-1.1-.9-2-2-2zm0 16H8V7h11v14z"/></svg></button></code></pre><h2 id="分区裁剪" style="position:relative"><a href="#%E5%88%86%E5%8C%BA%E8%A3%81%E5%89%AA" aria-label="分区裁剪 permalink" class="anchor before"><svg aria-hidden="true" focusable="false" height="16" version="1.1" viewbox="0 0 16 16" width="16"><path fill-rule="evenodd" d="M4 9h1v1H4c-1.5 0-3-1.69-3-3.5S2.55 3 4 3h4c1.45 0 3 1.69 3 3.5 0 1.41-.91 2.72-2 3.25V8.59c.58-.45 1-1.27 1-2.09C10 5.22 8.98 4 8 4H4c-.98 0-2 1.22-2 2.5S3 9 4 9zm9-3h-1v1h1c1 0 2 1.22 2 2.5S13.98 12 13 12H9c-.98 0-2-1.22-2-2.5 0-.83.42-1.64 1-2.09V6.25c-1.09.53-2 1.84-2 3.25C6 11.31 7.55 13 9 13h4c1.45 0 3-1.69 3-3.5S14.5 6 13 6z"/></svg></a>分区裁剪</h2><p>有一个优化叫做<a href="/zh/tidb/stable/partition-pruning">“分区裁剪”</a>，它基于一个非常简单的概念：不需要扫描那些匹配不上的分区。</p><p>假设创建一个分区表 <code>t1</code>：</p><pre><code class="hljs language-sql"><div class="MuiBox-root css-1qhimia"><span class="hljs-keyword">CREATE</span> <span class="hljs-keyword">TABLE</span> t1 ( fname <span class="hljs-type">VARCHAR</span>(<span class="hljs-number">50</span>) <span class="hljs-keyword">NOT</span> <span class="hljs-keyword">NULL</span>, lname <span class="hljs-type">VARCHAR</span>(<span class="hljs-number">50</span>) <span class="hljs-keyword">NOT</span> <span class="hljs-keyword">NULL</span>, region_code TINYINT UNSIGNED <span class="hljs-keyword">NOT</span> <span class="hljs-keyword">NULL</span>, dob <span class="hljs-type">DATE</span> <span class="hljs-keyword">NOT</span> <span class="hljs-keyword">NULL</span> <span class="hljs-keyword">PARTITION</span> <span class="hljs-keyword">BY</span> <span class="hljs-keyword">RANGE</span>( region_code ) ( <span class="hljs-keyword">PARTITION</span> p0 <span class="hljs-keyword">VALUES</span> LESS THAN (<span class="hljs-number">64</span>), <span class="hljs-keyword">PARTITION</span> p1 <span class="hljs-keyword">VALUES</span> LESS THAN (<span class="hljs-number">128</span>), <span class="hljs-keyword">PARTITION</span> p2 <span class="hljs-keyword">VALUES</span> LESS THAN (<span class="hljs-number">192</span>), <span class="hljs-keyword">PARTITION</span> p3 <span class="hljs-keyword">VALUES</span> LESS THAN MAXVALUE </div><button class="MuiButtonBase-root MuiIconButton-root MuiIconButton-sizeSmall css-1rmx1rm" tabindex="0" type="button" aria-label="Toggle code wrap"><svg class="MuiSvgIcon-root MuiSvgIcon-fontSizeInherit css-1cw4hi4" focusable="false" aria-hidden="true" viewbox="0 0 24 24" data-testid="WrapTextIcon"><path d="M4 19h6v-2H4v2zM20 5H4v2h16V5zm-3 6H4v2h13.25c1.1 0 2 .9 2 2s-.9 2-2 2H15v-2l-3 3 3 3v-2h2c2.21 0 4-1.79 4-4s-1.79-4-4-4z"/></svg></button><button class="MuiButtonBase-root MuiIconButton-root MuiIconButton-sizeSmall css-fxo539" tabindex="0" type="button" aria-label="copy"><svg class="MuiSvgIcon-root MuiSvgIcon-fontSizeInherit css-1cw4hi4" focusable="false" aria-hidden="true" viewbox="0 0 24 24" data-testid="ContentCopyIcon"><path d="M16 1H4c-1.1 0-2 .9-2 2v14h2V3h12V1zm3 4H8c-1.1 0-2 .9-2 2v14c0 1.1.9 2 2 2h11c1.1 0 2-.9 2-2V7c0-1.1-.9-2-2-2zm0 16H8V7h11v14z"/></svg></button></code></pre><p>如果你想获得这个 select 语句的结果：</p><pre><code class="hljs language-sql"><div class="MuiBox-root css-1qhimia"><span class="hljs-keyword">SELECT</span> fname, lname, region_code, dob <span class="hljs-keyword">FROM</span> t1 <span class="hljs-keyword">WHERE</span> region_code <span class="hljs-operator">&gt;</span> <span class="hljs-number">125</span> <span class="hljs-keyword">AND</span> region_code <span class="hljs-operator">&lt;</span> <span class="hljs-number">130</span>; </div><button class="MuiButtonBase-root MuiIconButton-root MuiIconButton-sizeSmall css-1rmx1rm" tabindex="0" type="button" aria-label="Toggle code wrap"><svg class="MuiSvgIcon-root MuiSvgIcon-fontSizeInherit css-1cw4hi4" focusable="false" aria-hidden="true" viewbox="0 0 24 24" data-testid="WrapTextIcon"><path d="M4 19h6v-2H4v2zM20 5H4v2h16V5zm-3 6H4v2h13.25c1.1 0 2 .9 2 2s-.9 2-2 2H15v-2l-3 3 3 3v-2h2c2.21 0 4-1.79 4-4s-1.79-4-4-4z"/></svg></button><button class="MuiButtonBase-root MuiIconButton-root MuiIconButton-sizeSmall css-fxo539" tabindex="0" type="button" aria-label="copy"><svg class="MuiSvgIcon-root MuiSvgIcon-fontSizeInherit css-1cw4hi4" focusable="false" aria-hidden="true" viewbox="0 0 24 24" data-testid="ContentCopyIcon"><path d="M16 1H4c-1.1 0-2 .9-2 2v14h2V3h12V1zm3 4H8c-1.1 0-2 .9-2 2v14c0 1.1.9 2 2 2h11c1.1 0 2-.9 2-2V7c0-1.1-.9-2-2-2zm0 16H8V7h11v14z"/></svg></button></code></pre><p>很显然，结果必然是在分区 <code>p1</code> 或者 <code>p2</code> 里面，也就是说，我们只需要在 <code>p1</code> 和 <code>p2</code> 里面去搜索匹配的行。去掉不必要的分区就是所谓的裁剪。优化器如果能裁剪掉一部分的分区，则执行会快于处理整个不做分区的表的相同查询。</p><p>优化器可以通过 where 条件裁剪的两个场景：</p><ul><li>partition_column = constant</li><li>partition_column IN (constant1, constant2, ..., constantN)</li></ul><p>分区裁剪暂不支持 <code>LIKE</code> 语句。</p><h3 id="分区裁剪生效的场景" style="position:relative"><a href="#%E5%88%86%E5%8C%BA%E8%A3%81%E5%89%AA%E7%94%9F%E6%95%88%E7%9A%84%E5%9C%BA%E6%99%AF" aria-label="分区裁剪生效的场景 permalink" class="anchor before"><svg aria-hidden="true" focusable="false" height="16" version="1.1" viewbox="0 0 16 16" width="16"><path fill-rule="evenodd" d="M4 9h1v1H4c-1.5 0-3-1.69-3-3.5S2.55 3 4 3h4c1.45 0 3 1.69 3 3.5 0 1.41-.91 2.72-2 3.25V8.59c.58-.45 1-1.27 1-2.09C10 5.22 8.98 4 8 4H4c-.98 0-2 1.22-2 2.5S3 9 4 9zm9-3h-1v1h1c1 0 2 1.22 2 2.5S13.98 12 13 12H9c-.98 0-2-1.22-2-2.5 0-.83.42-1.64 1-2.09V6.25c-1.09.53-2 1.84-2 3.25C6 11.31 7.55 13 9 13h4c1.45 0 3-1.69 3-3.5S14.5 6 13 6z"/></svg></a>分区裁剪生效的场景</h3><ol><li><p>分区裁剪需要使用分区表上面的查询条件，所以根据优化器的优化规则，如果查询条件不能下推到分区表，则相应的查询语句无法执行分区裁剪。</p><p>例如：</p><pre><code class="hljs language-sql"><div class="MuiBox-root css-1qhimia"><span class="hljs-keyword">create</span> <span class="hljs-keyword">table</span> t1 (x <span class="hljs-type">int</span>) <span class="hljs-keyword">partition</span> <span class="hljs-keyword">by</span> <span class="hljs-keyword">range</span> (x) ( <span class="hljs-keyword">partition</span> p0 <span class="hljs-keyword">values</span> less than (<span class="hljs-number">5</span>), <span class="hljs-keyword">partition</span> p1 <span class="hljs-keyword">values</span> less than (<span class="hljs-number">10</span>)); <span class="hljs-keyword">create</span> <span class="hljs-keyword">table</span> t2 (x <span class="hljs-type">int</span>); </div><button class="MuiButtonBase-root MuiIconButton-root MuiIconButton-sizeSmall css-1rmx1rm" tabindex="0" type="button" aria-label="Toggle code wrap"><svg class="MuiSvgIcon-root MuiSvgIcon-fontSizeInherit css-1cw4hi4" focusable="false" aria-hidden="true" viewbox="0 0 24 24" data-testid="WrapTextIcon"><path d="M4 19h6v-2H4v2zM20 5H4v2h16V5zm-3 6H4v2h13.25c1.1 0 2 .9 2 2s-.9 2-2 2H15v-2l-3 3 3 3v-2h2c2.21 0 4-1.79 4-4s-1.79-4-4-4z"/></svg></button><button class="MuiButtonBase-root MuiIconButton-root MuiIconButton-sizeSmall css-fxo539" tabindex="0" type="button" aria-label="copy"><svg class="MuiSvgIcon-root MuiSvgIcon-fontSizeInherit css-1cw4hi4" focusable="false" aria-hidden="true" viewbox="0 0 24 24" data-testid="ContentCopyIcon"><path d="M16 1H4c-1.1 0-2 .9-2 2v14h2V3h12V1zm3 4H8c-1.1 0-2 .9-2 2v14c0 1.1.9 2 2 2h11c1.1 0 2-.9 2-2V7c0-1.1-.9-2-2-2zm0 16H8V7h11v14z"/></svg></button></code></pre><pre><code class="hljs language-sql"><div class="MuiBox-root css-1qhimia">explain <span class="hljs-keyword">select</span> <span class="hljs-operator">*</span> <span class="hljs-keyword">from</span> t1 <span class="hljs-keyword">left</span> <span class="hljs-keyword">join</span> t2 <span class="hljs-keyword">on</span> t1.x <span class="hljs-operator">=</span> t2.x <span class="hljs-keyword">where</span> t2.x <span class="hljs-operator">&gt;</span> <span class="hljs-number">5</span>; </div><button class="MuiButtonBase-root MuiIconButton-root MuiIconButton-sizeSmall css-1rmx1rm" tabindex="0" type="button" aria-label="Toggle code wrap"><svg class="MuiSvgIcon-root MuiSvgIcon-fontSizeInherit css-1cw4hi4" focusable="false" aria-hidden="true" viewbox="0 0 24 24" data-testid="WrapTextIcon"><path d="M4 19h6v-2H4v2zM20 5H4v2h16V5zm-3 6H4v2h13.25c1.1 0 2 .9 2 2s-.9 2-2 2H15v-2l-3 3 3 3v-2h2c2.21 0 4-1.79 4-4s-1.79-4-4-4z"/></svg></button><button class="MuiButtonBase-root MuiIconButton-root MuiIconButton-sizeSmall css-fxo539" tabindex="0" type="button" aria-label="copy"><svg class="MuiSvgIcon-root MuiSvgIcon-fontSizeInherit css-1cw4hi4" focusable="false" aria-hidden="true" viewbox="0 0 24 24" data-testid="ContentCopyIcon"><path d="M16 1H4c-1.1 0-2 .9-2 2v14h2V3h12V1zm3 4H8c-1.1 0-2 .9-2 2v14c0 1.1.9 2 2 2h11c1.1 0 2-.9 2-2V7c0-1.1-.9-2-2-2zm0 16H8V7h11v14z"/></svg></button></code></pre><p>在这个查询中，外连接可以简化成内连接，然后由 <code>t1.x = t2.x</code> 和 <code>t2.x &gt; 5</code> 可以推出条件 <code>t1.x &gt; 5</code>，于是可以分区裁剪并且只使用 <code>p1</code> 分区。</p><pre><code class="hljs language-sql"><div class="MuiBox-root css-1qhimia">explain <span class="hljs-keyword">select</span> <span class="hljs-operator">*</span> <span class="hljs-keyword">from</span> t1 <span class="hljs-keyword">left</span> <span class="hljs-keyword">join</span> t2 <span class="hljs-keyword">on</span> t1.x <span class="hljs-operator">=</span> t2.x <span class="hljs-keyword">and</span> t2.x <span class="hljs-operator">&gt;</span> <span class="hljs-number">5</span>; </div><button class="MuiButtonBase-root MuiIconButton-root MuiIconButton-sizeSmall css-1rmx1rm" tabindex="0" type="button" aria-label="Toggle code wrap"><svg class="MuiSvgIcon-root MuiSvgIcon-fontSizeInherit css-1cw4hi4" focusable="false" aria-hidden="true" viewbox="0 0 24 24" data-testid="WrapTextIcon"><path d="M4 19h6v-2H4v2zM20 5H4v2h16V5zm-3 6H4v2h13.25c1.1 0 2 .9 2 2s-.9 2-2 2H15v-2l-3 3 3 3v-2h2c2.21 0 4-1.79 4-4s-1.79-4-4-4z"/></svg></button><button class="MuiButtonBase-root MuiIconButton-root MuiIconButton-sizeSmall css-fxo539" tabindex="0" type="button" aria-label="copy"><svg class="MuiSvgIcon-root MuiSvgIcon-fontSizeInherit css-1cw4hi4" focusable="false" aria-hidden="true" viewbox="0 0 24 24" data-testid="ContentCopyIcon"><path d="M16 1H4c-1.1 0-2 .9-2 2v14h2V3h12V1zm3 4H8c-1.1 0-2 .9-2 2v14c0 1.1.9 2 2 2h11c1.1 0 2-.9 2-2V7c0-1.1-.9-2-2-2zm0 16H8V7h11v14z"/></svg></button></code></pre><p>这个查询中的 <code>t2.x &gt; 5</code> 条件不能下推到 <code>t1</code> 分区表上面，因此 <code>t1</code> 无法分区裁剪。</p></li><li><p>由于分区裁剪的规则优化是在查询计划的生成阶段，对于执行阶段才能获取到过滤条件的场景，无法利用分区裁剪的优化。</p><p>例如：</p><pre><code class="hljs language-sql"><div class="MuiBox-root css-1qhimia"><span class="hljs-keyword">create</span> <span class="hljs-keyword">table</span> t1 (x <span class="hljs-type">int</span>) <span class="hljs-keyword">partition</span> <span class="hljs-keyword">by</span> <span class="hljs-keyword">range</span> (x) ( <span class="hljs-keyword">partition</span> p0 <span class="hljs-keyword">values</span> less than (<span class="hljs-number">5</span>), <span class="hljs-keyword">partition</span> p1 <span class="hljs-keyword">values</span> less than (<span class="hljs-number">10</span>)); </div><button class="MuiButtonBase-root MuiIconButton-root MuiIconButton-sizeSmall css-1rmx1rm" tabindex="0" type="button" aria-label="Toggle code wrap"><svg class="MuiSvgIcon-root MuiSvgIcon-fontSizeInherit css-1cw4hi4" focusable="false" aria-hidden="true" viewbox="0 0 24 24" data-testid="WrapTextIcon"><path d="M4 19h6v-2H4v2zM20 5H4v2h16V5zm-3 6H4v2h13.25c1.1 0 2 .9 2 2s-.9 2-2 2H15v-2l-3 3 3 3v-2h2c2.21 0 4-1.79 4-4s-1.79-4-4-4z"/></svg></button><button class="MuiButtonBase-root MuiIconButton-root MuiIconButton-sizeSmall css-fxo539" tabindex="0" type="button" aria-label="copy"><svg class="MuiSvgIcon-root MuiSvgIcon-fontSizeInherit css-1cw4hi4" focusable="false" aria-hidden="true" viewbox="0 0 24 24" data-testid="ContentCopyIcon"><path d="M16 1H4c-1.1 0-2 .9-2 2v14h2V3h12V1zm3 4H8c-1.1 0-2 .9-2 2v14c0 1.1.9 2 2 2h11c1.1 0 2-.9 2-2V7c0-1.1-.9-2-2-2zm0 16H8V7h11v14z"/></svg></button></code></pre><pre><code class="hljs language-sql"><div class="MuiBox-root css-1qhimia">explain <span class="hljs-keyword">select</span> <span class="hljs-operator">*</span> <span class="hljs-keyword">from</span> t2 <span class="hljs-keyword">where</span> x <span class="hljs-operator">&lt;</span> (<span class="hljs-keyword">select</span> <span class="hljs-operator">*</span> <span class="hljs-keyword">from</span> t1 <span class="hljs-keyword">where</span> t2.x <span class="hljs-operator">&lt;</span> t1.x <span class="hljs-keyword">and</span> t2.x <span class="hljs-operator">&lt;</span> <span class="hljs-number">2</span>); </div><button class="MuiButtonBase-root MuiIconButton-root MuiIconButton-sizeSmall css-1rmx1rm" tabindex="0" type="button" aria-label="Toggle code wrap"><svg class="MuiSvgIcon-root MuiSvgIcon-fontSizeInherit css-1cw4hi4" focusable="false" aria-hidden="true" viewbox="0 0 24 24" data-testid="WrapTextIcon"><path d="M4 19h6v-2H4v2zM20 5H4v2h16V5zm-3 6H4v2h13.25c1.1 0 2 .9 2 2s-.9 2-2 2H15v-2l-3 3 3 3v-2h2c2.21 0 4-1.79 4-4s-1.79-4-4-4z"/></svg></button><button class="MuiButtonBase-root MuiIconButton-root MuiIconButton-sizeSmall css-fxo539" tabindex="0" type="button" aria-label="copy"><svg class="MuiSvgIcon-root MuiSvgIcon-fontSizeInherit css-1cw4hi4" focusable="false" aria-hidden="true" viewbox="0 0 24 24" data-testid="ContentCopyIcon"><path d="M16 1H4c-1.1 0-2 .9-2 2v14h2V3h12V1zm3 4H8c-1.1 0-2 .9-2 2v14c0 1.1.9 2 2 2h11c1.1 0 2-.9 2-2V7c0-1.1-.9-2-2-2zm0 16H8V7h11v14z"/></svg></button></code></pre><p>这个查询每从 <code>t2</code> 读取一行，都会去分区表 <code>t1</code> 上进行查询，理论上这时会满足 <code>t1.x &gt; val</code> 的过滤条件，但实际上由于分区裁剪只作用于查询计划生成阶段，而不是执行阶段，因而不会做裁剪。</p></li><li><p>由于当前实现中的一处限制，对于查询条件无法下推到 TiKV 的表达式，不支持分区裁剪。</p><p>对于一个函数表达式 <code>fn(col)</code>，如果 TiKV 支持这个函数 <code>fn</code>，则在查询优化做谓词下推的时候，<code>fn(col)</code> 会被推到叶子节点（也就是分区），因而能够执行分区裁剪。</p><p>如果 TiKV 不支持 <code>fn</code>，则优化阶段不会把 <code>fn(col)</code> 推到叶子节点，而是在叶子上面连接一个 Selection 节点，分区裁剪的实现没有处理这种父节点的 Selection 中的条件，因此对不能下推到 TiKV 的表达式不支持分区裁剪。</p></li><li><p>对于 Hash 和 Key 分区类型，只有等值比较的查询条件能够支持分区裁剪。</p></li><li><p>对于 Range 分区类型，分区表达式必须是 <code>col</code> 或者 <code>fn(col)</code> 的简单形式，查询条件是 <code>&gt;</code>、<code>&lt;</code>、<code>=</code>、<code>&gt;=</code>、<code>&lt;=</code> 时才能支持分区裁剪。如果分区表达式是 <code>fn(col)</code> 形式，还要求 <code>fn</code> 必须是单调函数，才有可能分区裁剪。</p><p>这里单调函数是指某个函数 <code>fn</code> 满足条件：对于任意 <code>x</code> <code>y</code>，如果 <code>x &gt; y</code>，则 <code>fn(x) &gt; fn(y)</code>。</p><p>这种是严格递增的单调函数，非严格递增的单调函数也可以符合分区裁剪要求，只要函数 <code>fn</code> 满足：对于任意 <code>x</code> <code>y</code>，如果 <code>x &gt; y</code>，则 <code>fn(x) &gt;= fn(y)</code>。</p><p>理论上所有满足单调条件（严格或者非严格）的函数都是可以支持分区裁剪。实际上，目前 TiDB 已经支持的单调函数只有：</p><ul><li><a href="/zh/tidb/stable/date-and-time-functions"><code>UNIX_TIMESTAMP()</code></a></li><li><a href="/zh/tidb/stable/date-and-time-functions"><code>TO_DAYS()</code></a></li></ul><p>例如，分区表达式是简单列的情况：</p><pre><code class="hljs language-sql"><div class="MuiBox-root css-1qhimia"><span class="hljs-keyword">create</span> <span class="hljs-keyword">table</span> t (id <span class="hljs-type">int</span>) <span class="hljs-keyword">partition</span> <span class="hljs-keyword">by</span> <span class="hljs-keyword">range</span> (id) ( <span class="hljs-keyword">partition</span> p0 <span class="hljs-keyword">values</span> less than (<span class="hljs-number">5</span>), <span class="hljs-keyword">partition</span> p1 <span class="hljs-keyword">values</span> less than (<span class="hljs-number">10</span>)); <span class="hljs-keyword">select</span> <span class="hljs-operator">*</span> <span class="hljs-keyword">from</span> t <span class="hljs-keyword">where</span> id <span class="hljs-operator">&gt;</span> <span class="hljs-number">6</span>; </div><button class="MuiButtonBase-root MuiIconButton-root MuiIconButton-sizeSmall css-1rmx1rm" tabindex="0" type="button" aria-label="Toggle code wrap"><svg class="MuiSvgIcon-root MuiSvgIcon-fontSizeInherit css-1cw4hi4" focusable="false" aria-hidden="true" viewbox="0 0 24 24" data-testid="WrapTextIcon"><path d="M4 19h6v-2H4v2zM20 5H4v2h16V5zm-3 6H4v2h13.25c1.1 0 2 .9 2 2s-.9 2-2 2H15v-2l-3 3 3 3v-2h2c2.21 0 4-1.79 4-4s-1.79-4-4-4z"/></svg></button><button class="MuiButtonBase-root MuiIconButton-root MuiIconButton-sizeSmall css-fxo539" tabindex="0" type="button" aria-label="copy"><svg class="MuiSvgIcon-root MuiSvgIcon-fontSizeInherit css-1cw4hi4" focusable="false" aria-hidden="true" viewbox="0 0 24 24" data-testid="ContentCopyIcon"><path d="M16 1H4c-1.1 0-2 .9-2 2v14h2V3h12V1zm3 4H8c-1.1 0-2 .9-2 2v14c0 1.1.9 2 2 2h11c1.1 0 2-.9 2-2V7c0-1.1-.9-2-2-2zm0 16H8V7h11v14z"/></svg></button></code></pre><p>分区表达式是 <code>fn(col)</code> 的形式，<code>fn</code> 是我们支持的单调函数 <code>to_days</code>：</p><pre><code class="hljs language-sql"><div class="MuiBox-root css-1qhimia"><span class="hljs-keyword">create</span> <span class="hljs-keyword">table</span> t (dt datetime) <span class="hljs-keyword">partition</span> <span class="hljs-keyword">by</span> <span class="hljs-keyword">range</span> (to_days(id)) ( <span class="hljs-keyword">partition</span> p0 <span class="hljs-keyword">values</span> less than (to_days(<span class="hljs-string">'2020-04-01'</span>)), <span class="hljs-keyword">partition</span> p1 <span class="hljs-keyword">values</span> less than (to_days(<span class="hljs-string">'2020-05-01'</span>))); <span class="hljs-keyword">select</span> <span class="hljs-operator">*</span> <span class="hljs-keyword">from</span> t <span class="hljs-keyword">where</span> dt <span class="hljs-operator">&gt;</span> <span class="hljs-string">'2020-04-18'</span>; </div><button class="MuiButtonBase-root MuiIconButton-root MuiIconButton-sizeSmall css-1rmx1rm" tabindex="0" type="button" aria-label="Toggle code wrap"><svg class="MuiSvgIcon-root MuiSvgIcon-fontSizeInherit css-1cw4hi4" focusable="false" aria-hidden="true" viewbox="0 0 24 24" data-testid="WrapTextIcon"><path d="M4 19h6v-2H4v2zM20 5H4v2h16V5zm-3 6H4v2h13.25c1.1 0 2 .9 2 2s-.9 2-2 2H15v-2l-3 3 3 3v-2h2c2.21 0 4-1.79 4-4s-1.79-4-4-4z"/></svg></button><button class="MuiButtonBase-root MuiIconButton-root MuiIconButton-sizeSmall css-fxo539" tabindex="0" type="button" aria-label="copy"><svg class="MuiSvgIcon-root MuiSvgIcon-fontSizeInherit css-1cw4hi4" focusable="false" aria-hidden="true" viewbox="0 0 24 24" data-testid="ContentCopyIcon"><path d="M16 1H4c-1.1 0-2 .9-2 2v14h2V3h12V1zm3 4H8c-1.1 0-2 .9-2 2v14c0 1.1.9 2 2 2h11c1.1 0 2-.9 2-2V7c0-1.1-.9-2-2-2zm0 16H8V7h11v14z"/></svg></button></code></pre><p>有一处例外是 <code>floor(unix_timestamp(ts))</code> 作为分区表达式，TiDB 针对这个场景做了特殊处理，可以支持分区裁剪。</p><pre><code class="hljs language-sql"><div class="MuiBox-root css-1qhimia"><span class="hljs-keyword">create</span> <span class="hljs-keyword">table</span> t (ts <span class="hljs-type">timestamp</span>(<span class="hljs-number">3</span>) <span class="hljs-keyword">not</span> <span class="hljs-keyword">null</span> <span class="hljs-keyword">default</span> <span class="hljs-built_in">current_timestamp</span>(<span class="hljs-number">3</span>)) <span class="hljs-keyword">partition</span> <span class="hljs-keyword">by</span> <span class="hljs-keyword">range</span> (<span class="hljs-built_in">floor</span>(unix_timestamp(ts))) ( <span class="hljs-keyword">partition</span> p0 <span class="hljs-keyword">values</span> less than (unix_timestamp(<span class="hljs-string">'2020-04-01 00:00:00'</span>)), <span class="hljs-keyword">partition</span> p1 <span class="hljs-keyword">values</span> less than (unix_timestamp(<span class="hljs-string">'2020-05-01 00:00:00'</span>))); <span class="hljs-keyword">select</span> <span class="hljs-operator">*</span> <span class="hljs-keyword">from</span> t <span class="hljs-keyword">where</span> ts <span class="hljs-operator">&gt;</span> <span class="hljs-string">'2020-04-18 02:00:42.123'</span>; </div><button class="MuiButtonBase-root MuiIconButton-root MuiIconButton-sizeSmall css-1rmx1rm" tabindex="0" type="button" aria-label="Toggle code wrap"><svg class="MuiSvgIcon-root MuiSvgIcon-fontSizeInherit css-1cw4hi4" focusable="false" aria-hidden="true" viewbox="0 0 24 24" data-testid="WrapTextIcon"><path d="M4 19h6v-2H4v2zM20 5H4v2h16V5zm-3 6H4v2h13.25c1.1 0 2 .9 2 2s-.9 2-2 2H15v-2l-3 3 3 3v-2h2c2.21 0 4-1.79 4-4s-1.79-4-4-4z"/></svg></button><button class="MuiButtonBase-root MuiIconButton-root MuiIconButton-sizeSmall css-fxo539" tabindex="0" type="button" aria-label="copy"><svg class="MuiSvgIcon-root MuiSvgIcon-fontSizeInherit css-1cw4hi4" focusable="false" aria-hidden="true" viewbox="0 0 24 24" data-testid="ContentCopyIcon"><path d="M16 1H4c-1.1 0-2 .9-2 2v14h2V3h12V1zm3 4H8c-1.1 0-2 .9-2 2v14c0 1.1.9 2 2 2h11c1.1 0 2-.9 2-2V7c0-1.1-.9-2-2-2zm0 16H8V7h11v14z"/></svg></button></code></pre></li></ol><h2 id="分区选择" style="position:relative"><a href="#%E5%88%86%E5%8C%BA%E9%80%89%E6%8B%A9" aria-label="分区选择 permalink" class="anchor before"><svg aria-hidden="true" focusable="false" height="16" version="1.1" viewbox="0 0 16 16" width="16"><path fill-rule="evenodd" d="M4 9h1v1H4c-1.5 0-3-1.69-3-3.5S2.55 3 4 3h4c1.45 0 3 1.69 3 3.5 0 1.41-.91 2.72-2 3.25V8.59c.58-.45 1-1.27 1-2.09C10 5.22 8.98 4 8 4H4c-.98 0-2 1.22-2 2.5S3 9 4 9zm9-3h-1v1h1c1 0 2 1.22 2 2.5S13.98 12 13 12H9c-.98 0-2-1.22-2-2.5 0-.83.42-1.64 1-2.09V6.25c-1.09.53-2 1.84-2 3.25C6 11.31 7.55 13 9 13h4c1.45 0 3-1.69 3-3.5S14.5 6 13 6z"/></svg></a>分区选择</h2><p>SELECT 语句中支持分区选择。实现通过使用一个 <code>PARTITION</code> 选项实现。</p><pre><code class="hljs language-sql"><div class="MuiBox-root css-1qhimia"><span class="hljs-keyword">SET</span> @<span class="hljs-variable">@sql</span>_mode <span class="hljs-operator">=</span> <span class="hljs-string">''</span>; <span class="hljs-keyword">CREATE</span> <span class="hljs-keyword">TABLE</span> employees ( id <span class="hljs-type">INT</span> <span class="hljs-keyword">NOT</span> <span class="hljs-keyword">NULL</span> AUTO_INCREMENT <span class="hljs-keyword">PRIMARY</span> KEY, fname <span class="hljs-type">VARCHAR</span>(<span class="hljs-number">25</span>) <span class="hljs-keyword">NOT</span> <span class="hljs-keyword">NULL</span>, lname <span class="hljs-type">VARCHAR</span>(<span class="hljs-number">25</span>) <span class="hljs-keyword">NOT</span> <span class="hljs-keyword">NULL</span>, store_id <span class="hljs-type">INT</span> <span class="hljs-keyword">NOT</span> <span class="hljs-keyword">NULL</span>, department_id <span class="hljs-type">INT</span> <span class="hljs-keyword">NOT</span> <span class="hljs-keyword">NULL</span> <span class="hljs-keyword">PARTITION</span> <span class="hljs-keyword">BY</span> <span class="hljs-keyword">RANGE</span>(id) ( <span class="hljs-keyword">PARTITION</span> p0 <span class="hljs-keyword">VALUES</span> LESS THAN (<span class="hljs-number">5</span>), <span class="hljs-keyword">PARTITION</span> p1 <span class="hljs-keyword">VALUES</span> LESS THAN (<span class="hljs-number">10</span>), <span class="hljs-keyword">PARTITION</span> p2 <span class="hljs-keyword">VALUES</span> LESS THAN (<span class="hljs-number">15</span>), <span class="hljs-keyword">PARTITION</span> p3 <span class="hljs-keyword">VALUES</span> LESS THAN MAXVALUE <span class="hljs-keyword">INSERT</span> <span class="hljs-keyword">INTO</span> employees <span class="hljs-keyword">VALUES</span> (<span class="hljs-string">''</span>, <span class="hljs-string">'Bob'</span>, <span class="hljs-string">'Taylor'</span>, <span class="hljs-number">3</span>, <span class="hljs-number">2</span>), (<span class="hljs-string">''</span>, <span class="hljs-string">'Frank'</span>, <span class="hljs-string">'Williams'</span>, <span class="hljs-number">1</span>, <span class="hljs-number">2</span>), (<span class="hljs-string">''</span>, <span class="hljs-string">'Ellen'</span>, <span class="hljs-string">'Johnson'</span>, <span class="hljs-number">3</span>, <span class="hljs-number">4</span>), (<span class="hljs-string">''</span>, <span class="hljs-string">'Jim'</span>, <span class="hljs-string">'Smith'</span>, <span class="hljs-number">2</span>, <span class="hljs-number">4</span>), (<span class="hljs-string">''</span>, <span class="hljs-string">'Mary'</span>, <span class="hljs-string">'Jones'</span>, <span class="hljs-number">1</span>, <span class="hljs-number">1</span>), (<span class="hljs-string">''</span>, <span class="hljs-string">'Linda'</span>, <span class="hljs-string">'Black'</span>, <span class="hljs-number">2</span>, <span class="hljs-number">3</span>), (<span class="hljs-string">''</span>, <span class="hljs-string">'Ed'</span>, <span class="hljs-string">'Jones'</span>, <span class="hljs-number">2</span>, <span class="hljs-number">1</span>), (<span class="hljs-string">''</span>, <span class="hljs-string">'June'</span>, <span class="hljs-string">'Wilson'</span>, <span class="hljs-number">3</span>, <span class="hljs-number">1</span>), (<span class="hljs-string">''</span>, <span class="hljs-string">'Andy'</span>, <span class="hljs-string">'Smith'</span>, <span class="hljs-number">1</span>, <span class="hljs-number">3</span>), (<span class="hljs-string">''</span>, <span class="hljs-string">'Lou'</span>, <span class="hljs-string">'Waters'</span>, <span class="hljs-number">2</span>, <span class="hljs-number">4</span>), (<span class="hljs-string">''</span>, <span class="hljs-string">'Jill'</span>, <span class="hljs-string">'Stone'</span>, <span class="hljs-number">1</span>, <span class="hljs-number">4</span>), (<span class="hljs-string">''</span>, <span class="hljs-string">'Roger'</span>, <span class="hljs-string">'White'</span>, <span class="hljs-number">3</span>, <span class="hljs-number">2</span>), (<span class="hljs-string">''</span>, <span class="hljs-string">'Howard'</span>, <span class="hljs-string">'Andrews'</span>, <span class="hljs-number">1</span>, <span class="hljs-number">2</span>), (<span class="hljs-string">''</span>, <span class="hljs-string">'Fred'</span>, <span class="hljs-string">'Goldberg'</span>, <span class="hljs-number">3</span>, <span class="hljs-number">3</span>), (<span class="hljs-string">''</span>, <span class="hljs-string">'Barbara'</span>, <span class="hljs-string">'Brown'</span>, <span class="hljs-number">2</span>, <span class="hljs-number">3</span>), (<span class="hljs-string">''</span>, <span class="hljs-string">'Alice'</span>, <span class="hljs-string">'Rogers'</span>, <span class="hljs-number">2</span>, <span class="hljs-number">2</span>), (<span class="hljs-string">''</span>, <span class="hljs-string">'Mark'</span>, <span class="hljs-string">'Morgan'</span>, <span class="hljs-number">3</span>, <span class="hljs-number">3</span>), (<span class="hljs-string">''</span>, <span class="hljs-string">'Karen'</span>, <span class="hljs-string">'Cole'</span>, <span class="hljs-number">3</span>, <span class="hljs-number">2</span>); </div><button class="MuiButtonBase-root MuiIconButton-root MuiIconButton-sizeSmall css-1rmx1rm" tabindex="0" type="button" aria-label="Toggle code wrap"><svg class="MuiSvgIcon-root MuiSvgIcon-fontSizeInherit css-1cw4hi4" focusable="false" aria-hidden="true" viewbox="0 0 24 24" data-testid="WrapTextIcon"><path d="M4 19h6v-2H4v2zM20 5H4v2h16V5zm-3 6H4v2h13.25c1.1 0 2 .9 2 2s-.9 2-2 2H15v-2l-3 3 3 3v-2h2c2.21 0 4-1.79 4-4s-1.79-4-4-4z"/></svg></button><button class="MuiButtonBase-root MuiIconButton-root MuiIconButton-sizeSmall css-fxo539" tabindex="0" type="button" aria-label="copy"><svg class="MuiSvgIcon-root MuiSvgIcon-fontSizeInherit css-1cw4hi4" focusable="false" aria-hidden="true" viewbox="0 0 24 24" data-testid="ContentCopyIcon"><path d="M16 1H4c-1.1 0-2 .9-2 2v14h2V3h12V1zm3 4H8c-1.1 0-2 .9-2 2v14c0 1.1.9 2 2 2h11c1.1 0 2-.9 2-2V7c0-1.1-.9-2-2-2zm0 16H8V7h11v14z"/></svg></button></code></pre><p>你可以查看存储在分区 <code>p1</code> 中的行：</p><pre><code class="hljs language-sql"><div class="MuiBox-root css-1qhimia"><span class="hljs-keyword">SELECT</span> <span class="hljs-operator">*</span> <span class="hljs-keyword">FROM</span> employees <span class="hljs-keyword">PARTITION</span> (p1); </div><button class="MuiButtonBase-root MuiIconButton-root MuiIconButton-sizeSmall css-1rmx1rm" tabindex="0" type="button" aria-label="Toggle code wrap"><svg class="MuiSvgIcon-root MuiSvgIcon-fontSizeInherit css-1cw4hi4" focusable="false" aria-hidden="true" viewbox="0 0 24 24" data-testid="WrapTextIcon"><path d="M4 19h6v-2H4v2zM20 5H4v2h16V5zm-3 6H4v2h13.25c1.1 0 2 .9 2 2s-.9 2-2 2H15v-2l-3 3 3 3v-2h2c2.21 0 4-1.79 4-4s-1.79-4-4-4z"/></svg></button><button class="MuiButtonBase-root MuiIconButton-root MuiIconButton-sizeSmall css-fxo539" tabindex="0" type="button" aria-label="copy"><svg class="MuiSvgIcon-root MuiSvgIcon-fontSizeInherit css-1cw4hi4" focusable="false" aria-hidden="true" viewbox="0 0 24 24" data-testid="ContentCopyIcon"><path d="M16 1H4c-1.1 0-2 .9-2 2v14h2V3h12V1zm3 4H8c-1.1 0-2 .9-2 2v14c0 1.1.9 2 2 2h11c1.1 0 2-.9 2-2V7c0-1.1-.9-2-2-2zm0 16H8V7h11v14z"/></svg></button></code></pre><pre><code class="hljs language-"><div class="MuiBox-root css-1qhimia">+----|-------|--------|----------|---------------+ | id | fname | lname | store_id | department_id | +----|-------|--------|----------|---------------+ | 5 | Mary | Jones | 1 | 1 | | 6 | Linda | Black | 2 | 3 | | 7 | Ed | Jones | 2 | 1 | | 8 | June | Wilson | 3 | 1 | | 9 | Andy | Smith | 1 | 3 | +----|-------|--------|----------|---------------+ 5 rows in set (0.00 sec) </div><button class="MuiButtonBase-root MuiIconButton-root MuiIconButton-sizeSmall css-1rmx1rm" tabindex="0" type="button" aria-label="Toggle code wrap"><svg class="MuiSvgIcon-root MuiSvgIcon-fontSizeInherit css-1cw4hi4" focusable="false" aria-hidden="true" viewbox="0 0 24 24" data-testid="WrapTextIcon"><path d="M4 19h6v-2H4v2zM20 5H4v2h16V5zm-3 6H4v2h13.25c1.1 0 2 .9 2 2s-.9 2-2 2H15v-2l-3 3 3 3v-2h2c2.21 0 4-1.79 4-4s-1.79-4-4-4z"/></svg></button><button class="MuiButtonBase-root MuiIconButton-root MuiIconButton-sizeSmall css-fxo539" tabindex="0" type="button" aria-label="copy"><svg class="MuiSvgIcon-root MuiSvgIcon-fontSizeInherit css-1cw4hi4" focusable="false" aria-hidden="true" viewbox="0 0 24 24" data-testid="ContentCopyIcon"><path d="M16 1H4c-1.1 0-2 .9-2 2v14h2V3h12V1zm3 4H8c-1.1 0-2 .9-2 2v14c0 1.1.9 2 2 2h11c1.1 0 2-.9 2-2V7c0-1.1-.9-2-2-2zm0 16H8V7h11v14z"/></svg></button></code></pre><p>如果希望获得多个分区中的行，可以提供分区名的列表，用逗号隔开。例如，<code>SELECT * FROM employees PARTITION (p1, p2)</code> 返回分区 <code>p1</code> 和 <code>p2</code> 的所有行。</p><p>使用分区选择时，仍然可以使用 where 条件，以及 ORDER BY 和 LIMIT 等选项。使用 HAVING 和 GROUP BY 等聚合选项也是支持的。</p><pre><code class="hljs language-sql"><div class="MuiBox-root css-1qhimia"><span class="hljs-keyword">SELECT</span> <span class="hljs-operator">*</span> <span class="hljs-keyword">FROM</span> employees <span class="hljs-keyword">PARTITION</span> (p0, p2) <span class="hljs-keyword">WHERE</span> lname <span class="hljs-keyword">LIKE</span> <span class="hljs-string">'S%'</span>; </div><button class="MuiButtonBase-root MuiIconButton-root MuiIconButton-sizeSmall css-1rmx1rm" tabindex="0" type="button" aria-label="Toggle code wrap"><svg class="MuiSvgIcon-root MuiSvgIcon-fontSizeInherit css-1cw4hi4" focusable="false" aria-hidden="true" viewbox="0 0 24 24" data-testid="WrapTextIcon"><path d="M4 19h6v-2H4v2zM20 5H4v2h16V5zm-3 6H4v2h13.25c1.1 0 2 .9 2 2s-.9 2-2 2H15v-2l-3 3 3 3v-2h2c2.21 0 4-1.79 4-4s-1.79-4-4-4z"/></svg></button><button class="MuiButtonBase-root MuiIconButton-root MuiIconButton-sizeSmall css-fxo539" tabindex="0" type="button" aria-label="copy"><svg class="MuiSvgIcon-root MuiSvgIcon-fontSizeInherit css-1cw4hi4" focusable="false" aria-hidden="true" viewbox="0 0 24 24" data-testid="ContentCopyIcon"><path d="M16 1H4c-1.1 0-2 .9-2 2v14h2V3h12V1zm3 4H8c-1.1 0-2 .9-2 2v14c0 1.1.9 2 2 2h11c1.1 0 2-.9 2-2V7c0-1.1-.9-2-2-2zm0 16H8V7h11v14z"/></svg></button></code></pre><pre><code class="hljs language-"><div class="MuiBox-root css-1qhimia">+----|-------|-------|----------|---------------+ | id | fname | lname | store_id | department_id | +----|-------|-------|----------|---------------+ | 4 | Jim | Smith | 2 | 4 | | 11 | Jill | Stone | 1 | 4 | +----|-------|-------|----------|---------------+ 2 rows in set (0.00 sec) </div><button class="MuiButtonBase-root MuiIconButton-root MuiIconButton-sizeSmall css-1rmx1rm" tabindex="0" type="button" aria-label="Toggle code wrap"><svg class="MuiSvgIcon-root MuiSvgIcon-fontSizeInherit css-1cw4hi4" focusable="false" aria-hidden="true" viewbox="0 0 24 24" data-testid="WrapTextIcon"><path d="M4 19h6v-2H4v2zM20 5H4v2h16V5zm-3 6H4v2h13.25c1.1 0 2 .9 2 2s-.9 2-2 2H15v-2l-3 3 3 3v-2h2c2.21 0 4-1.79 4-4s-1.79-4-4-4z"/></svg></button><button class="MuiButtonBase-root MuiIconButton-root MuiIconButton-sizeSmall css-fxo539" tabindex="0" type="button" aria-label="copy"><svg class="MuiSvgIcon-root MuiSvgIcon-fontSizeInherit css-1cw4hi4" focusable="false" aria-hidden="true" viewbox="0 0 24 24" data-testid="ContentCopyIcon"><path d="M16 1H4c-1.1 0-2 .9-2 2v14h2V3h12V1zm3 4H8c-1.1 0-2 .9-2 2v14c0 1.1.9 2 2 2h11c1.1 0 2-.9 2-2V7c0-1.1-.9-2-2-2zm0 16H8V7h11v14z"/></svg></button></code></pre><pre><code class="hljs language-sql"><div class="MuiBox-root css-1qhimia"><span class="hljs-keyword">SELECT</span> id, CONCAT(fname, <span class="hljs-string">' '</span>, lname) <span class="hljs-keyword">AS</span> name <span class="hljs-keyword">FROM</span> employees <span class="hljs-keyword">PARTITION</span> (p0) <span class="hljs-keyword">ORDER</span> <span class="hljs-keyword">BY</span> lname; </div><button class="MuiButtonBase-root MuiIconButton-root MuiIconButton-sizeSmall css-1rmx1rm" tabindex="0" type="button" aria-label="Toggle code wrap"><svg class="MuiSvgIcon-root MuiSvgIcon-fontSizeInherit css-1cw4hi4" focusable="false" aria-hidden="true" viewbox="0 0 24 24" data-testid="WrapTextIcon"><path d="M4 19h6v-2H4v2zM20 5H4v2h16V5zm-3 6H4v2h13.25c1.1 0 2 .9 2 2s-.9 2-2 2H15v-2l-3 3 3 3v-2h2c2.21 0 4-1.79 4-4s-1.79-4-4-4z"/></svg></button><button class="MuiButtonBase-root MuiIconButton-root MuiIconButton-sizeSmall css-fxo539" tabindex="0" type="button" aria-label="copy"><svg class="MuiSvgIcon-root MuiSvgIcon-fontSizeInherit css-1cw4hi4" focusable="false" aria-hidden="true" viewbox="0 0 24 24" data-testid="ContentCopyIcon"><path d="M16 1H4c-1.1 0-2 .9-2 2v14h2V3h12V1zm3 4H8c-1.1 0-2 .9-2 2v14c0 1.1.9 2 2 2h11c1.1 0 2-.9 2-2V7c0-1.1-.9-2-2-2zm0 16H8V7h11v14z"/></svg></button></code></pre><pre><code class="hljs language-"><div class="MuiBox-root css-1qhimia">+----|----------------+ | id | name | +----|----------------+ | 3 | Ellen Johnson | | 4 | Jim Smith | | 1 | Bob Taylor | | 2 | Frank Williams | +----|----------------+ 4 rows in set (0.06 sec) </div><button class="MuiButtonBase-root MuiIconButton-root MuiIconButton-sizeSmall css-1rmx1rm" tabindex="0" type="button" aria-label="Toggle code wrap"><svg class="MuiSvgIcon-root MuiSvgIcon-fontSizeInherit css-1cw4hi4" focusable="false" aria-hidden="true" viewbox="0 0 24 24" data-testid="WrapTextIcon"><path d="M4 19h6v-2H4v2zM20 5H4v2h16V5zm-3 6H4v2h13.25c1.1 0 2 .9 2 2s-.9 2-2 2H15v-2l-3 3 3 3v-2h2c2.21 0 4-1.79 4-4s-1.79-4-4-4z"/></svg></button><button class="MuiButtonBase-root MuiIconButton-root MuiIconButton-sizeSmall css-fxo539" tabindex="0" type="button" aria-label="copy"><svg class="MuiSvgIcon-root MuiSvgIcon-fontSizeInherit css-1cw4hi4" focusable="false" aria-hidden="true" viewbox="0 0 24 24" data-testid="ContentCopyIcon"><path d="M16 1H4c-1.1 0-2 .9-2 2v14h2V3h12V1zm3 4H8c-1.1 0-2 .9-2 2v14c0 1.1.9 2 2 2h11c1.1 0 2-.9 2-2V7c0-1.1-.9-2-2-2zm0 16H8V7h11v14z"/></svg></button></code></pre><pre><code class="hljs language-sql"><div class="MuiBox-root css-1qhimia"><span class="hljs-keyword">SELECT</span> store_id, <span class="hljs-built_in">COUNT</span>(department_id) <span class="hljs-keyword">AS</span> c <span class="hljs-keyword">FROM</span> employees <span class="hljs-keyword">PARTITION</span> (p1,p2,p3) <span class="hljs-keyword">GROUP</span> <span class="hljs-keyword">BY</span> store_id <span class="hljs-keyword">HAVING</span> c <span class="hljs-operator">&gt;</span> <span class="hljs-number">4</span>; </div><button class="MuiButtonBase-root MuiIconButton-root MuiIconButton-sizeSmall css-1rmx1rm" tabindex="0" type="button" aria-label="Toggle code wrap"><svg class="MuiSvgIcon-root MuiSvgIcon-fontSizeInherit css-1cw4hi4" focusable="false" aria-hidden="true" viewbox="0 0 24 24" data-testid="WrapTextIcon"><path d="M4 19h6v-2H4v2zM20 5H4v2h16V5zm-3 6H4v2h13.25c1.1 0 2 .9 2 2s-.9 2-2 2H15v-2l-3 3 3 3v-2h2c2.21 0 4-1.79 4-4s-1.79-4-4-4z"/></svg></button><button class="MuiButtonBase-root MuiIconButton-root MuiIconButton-sizeSmall css-fxo539" tabindex="0" type="button" aria-label="copy"><svg class="MuiSvgIcon-root MuiSvgIcon-fontSizeInherit css-1cw4hi4" focusable="false" aria-hidden="true" viewbox="0 0 24 24" data-testid="ContentCopyIcon"><path d="M16 1H4c-1.1 0-2 .9-2 2v14h2V3h12V1zm3 4H8c-1.1 0-2 .9-2 2v14c0 1.1.9 2 2 2h11c1.1 0 2-.9 2-2V7c0-1.1-.9-2-2-2zm0 16H8V7h11v14z"/></svg></button></code></pre><pre><code class="hljs language-"><div class="MuiBox-root css-1qhimia">+---|----------+ | c | store_id | +---|----------+ | 5 | 2 | | 5 | 3 | +---|----------+ 2 rows in set (0.00 sec) </div><button class="MuiButtonBase-root MuiIconButton-root MuiIconButton-sizeSmall css-1rmx1rm" tabindex="0" type="button" aria-label="Toggle code wrap"><svg class="MuiSvgIcon-root MuiSvgIcon-fontSizeInherit css-1cw4hi4" focusable="false" aria-hidden="true" viewbox="0 0 24 24" data-testid="WrapTextIcon"><path d="M4 19h6v-2H4v2zM20 5H4v2h16V5zm-3 6H4v2h13.25c1.1 0 2 .9 2 2s-.9 2-2 2H15v-2l-3 3 3 3v-2h2c2.21 0 4-1.79 4-4s-1.79-4-4-4z"/></svg></button><button class="MuiButtonBase-root MuiIconButton-root MuiIconButton-sizeSmall css-fxo539" tabindex="0" type="button" aria-label="copy"><svg class="MuiSvgIcon-root MuiSvgIcon-fontSizeInherit css-1cw4hi4" focusable="false" aria-hidden="true" viewbox="0 0 24 24" data-testid="ContentCopyIcon"><path d="M16 1H4c-1.1 0-2 .9-2 2v14h2V3h12V1zm3 4H8c-1.1 0-2 .9-2 2v14c0 1.1.9 2 2 2h11c1.1 0 2-.9 2-2V7c0-1.1-.9-2-2-2zm0 16H8V7h11v14z"/></svg></button></code></pre><p>分支选择支持所有类型的分区表，无论是 Range 分区或是 Hash 分区等。对于 Hash 分区，如果没有指定分区名，会自动使用 <code>p0</code>、<code>p1</code>、<code>p2</code>、……、或 <code>pN-1</code> 作为分区名。</p><p>在 <code>INSERT ... SELECT</code> 的 <code>SELECT</code> 中也是可以使用分区选择的。</p><h2 id="分区的约束和限制" style="position:relative"><a href="#%E5%88%86%E5%8C%BA%E7%9A%84%E7%BA%A6%E6%9D%9F%E5%92%8C%E9%99%90%E5%88%B6" aria-label="分区的约束和限制 permalink" class="anchor before"><svg aria-hidden="true" focusable="false" height="16" version="1.1" viewbox="0 0 16 16" width="16"><path fill-rule="evenodd" d="M4 9h1v1H4c-1.5 0-3-1.69-3-3.5S2.55 3 4 3h4c1.45 0 3 1.69 3 3.5 0 1.41-.91 2.72-2 3.25V8.59c.58-.45 1-1.27 1-2.09C10 5.22 8.98 4 8 4H4c-.98 0-2 1.22-2 2.5S3 9 4 9zm9-3h-1v1h1c1 0 2 1.22 2 2.5S13.98 12 13 12H9c-.98 0-2-1.22-2-2.5 0-.83.42-1.64 1-2.09V6.25c-1.09.53-2 1.84-2 3.25C6 11.31 7.55 13 9 13h4c1.45 0 3-1.69 3-3.5S14.5 6 13 6z"/></svg></a>分区的约束和限制</h2><p>本节介绍当前 TiDB 分区表的一些约束和限制。</p><h3 id="分区键主键和唯一键" style="position:relative"><a href="#%E5%88%86%E5%8C%BA%E9%94%AE%E4%B8%BB%E9%94%AE%E5%92%8C%E5%94%AF%E4%B8%80%E9%94%AE" aria-label="分区键主键和唯一键 permalink" class="anchor before"><svg aria-hidden="true" focusable="false" height="16" version="1.1" viewbox="0 0 16 16" width="16"><path fill-rule="evenodd" d="M4 9h1v1H4c-1.5 0-3-1.69-3-3.5S2.55 3 4 3h4c1.45 0 3 1.69 3 3.5 0 1.41-.91 2.72-2 3.25V8.59c.58-.45 1-1.27 1-2.09C10 5.22 8.98 4 8 4H4c-.98 0-2 1.22-2 2.5S3 9 4 9zm9-3h-1v1h1c1 0 2 1.22 2 2.5S13.98 12 13 12H9c-.98 0-2-1.22-2-2.5 0-.83.42-1.64 1-2.09V6.25c-1.09.53-2 1.84-2 3.25C6 11.31 7.55 13 9 13h4c1.45 0 3-1.69 3-3.5S14.5 6 13 6z"/></svg></a>分区键，主键和唯一键</h3><p>本节讨论分区键，主键和唯一键之间的关系。一句话总结它们之间的关系要满足的规则：<strong>分区表的每个唯一键，必须包含分区表达式中用到的所有列</strong>。</p><blockquote><p>every unique key on the table must use every column in the table's partitioning expression.</p></blockquote><p>这里所指的唯一也包含了主键，因为根据主键的定义，主键必须是唯一的。例如，下面这些建表语句就是无效的：</p><pre><code class="hljs language-sql"><div class="MuiBox-root css-1qhimia"><span class="hljs-keyword">CREATE</span> <span class="hljs-keyword">TABLE</span> t1 ( col1 <span class="hljs-type">INT</span> <span class="hljs-keyword">NOT</span> <span class="hljs-keyword">NULL</span>, col2 <span class="hljs-type">DATE</span> <span class="hljs-keyword">NOT</span> <span class="hljs-keyword">NULL</span>, col3 <span class="hljs-type">INT</span> <span class="hljs-keyword">NOT</span> <span class="hljs-keyword">NULL</span>, col4 <span class="hljs-type">INT</span> <span class="hljs-keyword">NOT</span> <span class="hljs-keyword">NULL</span>, <span class="hljs-keyword">UNIQUE</span> KEY (col1, col2) <span class="hljs-keyword">PARTITION</span> <span class="hljs-keyword">BY</span> HASH(col3) PARTITIONS <span class="hljs-number">4</span>; <span class="hljs-keyword">CREATE</span> <span class="hljs-keyword">TABLE</span> t2 ( col1 <span class="hljs-type">INT</span> <span class="hljs-keyword">NOT</span> <span class="hljs-keyword">NULL</span>, col2 <span class="hljs-type">DATE</span> <span class="hljs-keyword">NOT</span> <span class="hljs-keyword">NULL</span>, col3 <span class="hljs-type">INT</span> <span class="hljs-keyword">NOT</span> <span class="hljs-keyword">NULL</span>, col4 <span class="hljs-type">INT</span> <span class="hljs-keyword">NOT</span> <span class="hljs-keyword">NULL</span>, <span class="hljs-keyword">UNIQUE</span> KEY (col1), <span class="hljs-keyword">UNIQUE</span> KEY (col3) <span class="hljs-keyword">PARTITION</span> <span class="hljs-keyword">BY</span> HASH(col1 <span class="hljs-operator">+</span> col3) PARTITIONS <span class="hljs-number">4</span>; </div><button class="MuiButtonBase-root MuiIconButton-root MuiIconButton-sizeSmall css-1rmx1rm" tabindex="0" type="button" aria-label="Toggle code wrap"><svg class="MuiSvgIcon-root MuiSvgIcon-fontSizeInherit css-1cw4hi4" focusable="false" aria-hidden="true" viewbox="0 0 24 24" data-testid="WrapTextIcon"><path d="M4 19h6v-2H4v2zM20 5H4v2h16V5zm-3 6H4v2h13.25c1.1 0 2 .9 2 2s-.9 2-2 2H15v-2l-3 3 3 3v-2h2c2.21 0 4-1.79 4-4s-1.79-4-4-4z"/></svg></button><button class="MuiButtonBase-root MuiIconButton-root MuiIconButton-sizeSmall css-fxo539" tabindex="0" type="button" aria-label="copy"><svg class="MuiSvgIcon-root MuiSvgIcon-fontSizeInherit css-1cw4hi4" focusable="false" aria-hidden="true" viewbox="0 0 24 24" data-testid="ContentCopyIcon"><path d="M16 1H4c-1.1 0-2 .9-2 2v14h2V3h12V1zm3 4H8c-1.1 0-2 .9-2 2v14c0 1.1.9 2 2 2h11c1.1 0 2-.9 2-2V7c0-1.1-.9-2-2-2zm0 16H8V7h11v14z"/></svg></button></code></pre><p>它们都是有唯一键但没有包含所有分区键的。</p><p>下面是一些合法的语句的例子：</p><pre><code class="hljs language-sql"><div class="MuiBox-root css-1qhimia"><span class="hljs-keyword">CREATE</span> <span class="hljs-keyword">TABLE</span> t1 ( col1 <span class="hljs-type">INT</span> <span class="hljs-keyword">NOT</span> <span class="hljs-keyword">NULL</span>, col2 <span class="hljs-type">DATE</span> <span class="hljs-keyword">NOT</span> <span class="hljs-keyword">NULL</span>, col3 <span class="hljs-type">INT</span> <span class="hljs-keyword">NOT</span> <span class="hljs-keyword">NULL</span>, col4 <span class="hljs-type">INT</span> <span class="hljs-keyword">NOT</span> <span class="hljs-keyword">NULL</span>, <span class="hljs-keyword">UNIQUE</span> KEY (col1, col2, col3) <span class="hljs-keyword">PARTITION</span> <span class="hljs-keyword">BY</span> HASH(col3) PARTITIONS <span class="hljs-number">4</span>; <span class="hljs-keyword">CREATE</span> <span class="hljs-keyword">TABLE</span> t2 ( col1 <span class="hljs-type">INT</span> <span class="hljs-keyword">NOT</span> <span class="hljs-keyword">NULL</span>, col2 <span class="hljs-type">DATE</span> <span class="hljs-keyword">NOT</span> <span class="hljs-keyword">NULL</span>, col3 <span class="hljs-type">INT</span> <span class="hljs-keyword">NOT</span> <span class="hljs-keyword">NULL</span>, col4 <span class="hljs-type">INT</span> <span class="hljs-keyword">NOT</span> <span class="hljs-keyword">NULL</span>, <span class="hljs-keyword">UNIQUE</span> KEY (col1, col3) <span class="hljs-keyword">PARTITION</span> <span class="hljs-keyword">BY</span> HASH(col1 <span class="hljs-operator">+</span> col3) PARTITIONS <span class="hljs-number">4</span>; </div><button class="MuiButtonBase-root MuiIconButton-root MuiIconButton-sizeSmall css-1rmx1rm" tabindex="0" type="button" aria-label="Toggle code wrap"><svg class="MuiSvgIcon-root MuiSvgIcon-fontSizeInherit css-1cw4hi4" focusable="false" aria-hidden="true" viewbox="0 0 24 24" data-testid="WrapTextIcon"><path d="M4 19h6v-2H4v2zM20 5H4v2h16V5zm-3 6H4v2h13.25c1.1 0 2 .9 2 2s-.9 2-2 2H15v-2l-3 3 3 3v-2h2c2.21 0 4-1.79 4-4s-1.79-4-4-4z"/></svg></button><button class="MuiButtonBase-root MuiIconButton-root MuiIconButton-sizeSmall css-fxo539" tabindex="0" type="button" aria-label="copy"><svg class="MuiSvgIcon-root MuiSvgIcon-fontSizeInherit css-1cw4hi4" focusable="false" aria-hidden="true" viewbox="0 0 24 24" data-testid="ContentCopyIcon"><path d="M16 1H4c-1.1 0-2 .9-2 2v14h2V3h12V1zm3 4H8c-1.1 0-2 .9-2 2v14c0 1.1.9 2 2 2h11c1.1 0 2-.9 2-2V7c0-1.1-.9-2-2-2zm0 16H8V7h11v14z"/></svg></button></code></pre><p>下例中会产生一个报错：</p><pre><code class="hljs language-sql"><div class="MuiBox-root css-1qhimia"><span class="hljs-keyword">CREATE</span> <span class="hljs-keyword">TABLE</span> t3 ( col1 <span class="hljs-type">INT</span> <span class="hljs-keyword">NOT</span> <span class="hljs-keyword">NULL</span>, col2 <span class="hljs-type">DATE</span> <span class="hljs-keyword">NOT</span> <span class="hljs-keyword">NULL</span>, col3 <span class="hljs-type">INT</span> <span class="hljs-keyword">NOT</span> <span class="hljs-keyword">NULL</span>, col4 <span class="hljs-type">INT</span> <span class="hljs-keyword">NOT</span> <span class="hljs-keyword">NULL</span>, <span class="hljs-keyword">UNIQUE</span> KEY (col1, col2), <span class="hljs-keyword">UNIQUE</span> KEY (col3) <span class="hljs-keyword">PARTITION</span> <span class="hljs-keyword">BY</span> HASH(col1 <span class="hljs-operator">+</span> col3) PARTITIONS <span class="hljs-number">4</span>; </div><button class="MuiButtonBase-root MuiIconButton-root MuiIconButton-sizeSmall css-1rmx1rm" tabindex="0" type="button" aria-label="Toggle code wrap"><svg class="MuiSvgIcon-root MuiSvgIcon-fontSizeInherit css-1cw4hi4" focusable="false" aria-hidden="true" viewbox="0 0 24 24" data-testid="WrapTextIcon"><path d="M4 19h6v-2H4v2zM20 5H4v2h16V5zm-3 6H4v2h13.25c1.1 0 2 .9 2 2s-.9 2-2 2H15v-2l-3 3 3 3v-2h2c2.21 0 4-1.79 4-4s-1.79-4-4-4z"/></svg></button><button class="MuiButtonBase-root MuiIconButton-root MuiIconButton-sizeSmall css-fxo539" tabindex="0" type="button" aria-label="copy"><svg class="MuiSvgIcon-root MuiSvgIcon-fontSizeInherit css-1cw4hi4" focusable="false" aria-hidden="true" viewbox="0 0 24 24" data-testid="ContentCopyIcon"><path d="M16 1H4c-1.1 0-2 .9-2 2v14h2V3h12V1zm3 4H8c-1.1 0-2 .9-2 2v14c0 1.1.9 2 2 2h11c1.1 0 2-.9 2-2V7c0-1.1-.9-2-2-2zm0 16H8V7h11v14z"/></svg></button></code></pre><pre><code class="hljs language-"><div class="MuiBox-root css-1qhimia">ERROR 1491 (HY000): A PRIMARY KEY must include all columns in the table's partitioning function </div><button class="MuiButtonBase-root MuiIconButton-root MuiIconButton-sizeSmall css-1rmx1rm" tabindex="0" type="button" aria-label="Toggle code wrap"><svg class="MuiSvgIcon-root MuiSvgIcon-fontSizeInherit css-1cw4hi4" focusable="false" aria-hidden="true" viewbox="0 0 24 24" data-testid="WrapTextIcon"><path d="M4 19h6v-2H4v2zM20 5H4v2h16V5zm-3 6H4v2h13.25c1.1 0 2 .9 2 2s-.9 2-2 2H15v-2l-3 3 3 3v-2h2c2.21 0 4-1.79 4-4s-1.79-4-4-4z"/></svg></button><button class="MuiButtonBase-root MuiIconButton-root MuiIconButton-sizeSmall css-fxo539" tabindex="0" type="button" aria-label="copy"><svg class="MuiSvgIcon-root MuiSvgIcon-fontSizeInherit css-1cw4hi4" focusable="false" aria-hidden="true" viewbox="0 0 24 24" data-testid="ContentCopyIcon"><path d="M16 1H4c-1.1 0-2 .9-2 2v14h2V3h12V1zm3 4H8c-1.1 0-2 .9-2 2v14c0 1.1.9 2 2 2h11c1.1 0 2-.9 2-2V7c0-1.1-.9-2-2-2zm0 16H8V7h11v14z"/></svg></button></code></pre><p>原因是 <code>col1</code> 和 <code>col3</code> 出现在分区键中，但是几个唯一键定义并没有完全包含它们，做如下修改后语句即为合法：</p><pre><code class="hljs language-sql"><div class="MuiBox-root css-1qhimia"><span class="hljs-keyword">CREATE</span> <span class="hljs-keyword">TABLE</span> t3 ( col1 <span class="hljs-type">INT</span> <span class="hljs-keyword">NOT</span> <span class="hljs-keyword">NULL</span>, col2 <span class="hljs-type">DATE</span> <span class="hljs-keyword">NOT</span> <span class="hljs-keyword">NULL</span>, col3 <span class="hljs-type">INT</span> <span class="hljs-keyword">NOT</span> <span class="hljs-keyword">NULL</span>, col4 <span class="hljs-type">INT</span> <span class="hljs-keyword">NOT</span> <span class="hljs-keyword">NULL</span>, <span class="hljs-keyword">UNIQUE</span> KEY (col1, col2, col3), <span class="hljs-keyword">UNIQUE</span> KEY (col1, col3) <span class="hljs-keyword">PARTITION</span> <span class="hljs-keyword">BY</span> HASH(col1 <span class="hljs-operator">+</span> col3) PARTITIONS <span class="hljs-number">4</span>; </div><button class="MuiButtonBase-root MuiIconButton-root MuiIconButton-sizeSmall css-1rmx1rm" tabindex="0" type="button" aria-label="Toggle code wrap"><svg class="MuiSvgIcon-root MuiSvgIcon-fontSizeInherit css-1cw4hi4" focusable="false" aria-hidden="true" viewbox="0 0 24 24" data-testid="WrapTextIcon"><path d="M4 19h6v-2H4v2zM20 5H4v2h16V5zm-3 6H4v2h13.25c1.1 0 2 .9 2 2s-.9 2-2 2H15v-2l-3 3 3 3v-2h2c2.21 0 4-1.79 4-4s-1.79-4-4-4z"/></svg></button><button class="MuiButtonBase-root MuiIconButton-root MuiIconButton-sizeSmall css-fxo539" tabindex="0" type="button" aria-label="copy"><svg class="MuiSvgIcon-root MuiSvgIcon-fontSizeInherit css-1cw4hi4" focusable="false" aria-hidden="true" viewbox="0 0 24 24" data-testid="ContentCopyIcon"><path d="M16 1H4c-1.1 0-2 .9-2 2v14h2V3h12V1zm3 4H8c-1.1 0-2 .9-2 2v14c0 1.1.9 2 2 2h11c1.1 0 2-.9 2-2V7c0-1.1-.9-2-2-2zm0 16H8V7h11v14z"/></svg></button></code></pre><p>下面这个表就没法做分区了，因为无论如何都不可能找到满足条件的分区键：</p><pre><code class="hljs language-sql"><div class="MuiBox-root css-1qhimia"><span class="hljs-keyword">CREATE</span> <span class="hljs-keyword">TABLE</span> t4 ( col1 <span class="hljs-type">INT</span> <span class="hljs-keyword">NOT</span> <span class="hljs-keyword">NULL</span>, col2 <span class="hljs-type">INT</span> <span class="hljs-keyword">NOT</span> <span class="hljs-keyword">NULL</span>, col3 <span class="hljs-type">INT</span> <span class="hljs-keyword">NOT</span> <span class="hljs-keyword">NULL</span>, col4 <span class="hljs-type">INT</span> <span class="hljs-keyword">NOT</span> <span class="hljs-keyword">NULL</span>, <span class="hljs-keyword">UNIQUE</span> KEY (col1, col3), <span class="hljs-keyword">UNIQUE</span> KEY (col2, col4) </div><button class="MuiButtonBase-root MuiIconButton-root MuiIconButton-sizeSmall css-1rmx1rm" tabindex="0" type="button" aria-label="Toggle code wrap"><svg class="MuiSvgIcon-root MuiSvgIcon-fontSizeInherit css-1cw4hi4" focusable="false" aria-hidden="true" viewbox="0 0 24 24" data-testid="WrapTextIcon"><path d="M4 19h6v-2H4v2zM20 5H4v2h16V5zm-3 6H4v2h13.25c1.1 0 2 .9 2 2s-.9 2-2 2H15v-2l-3 3 3 3v-2h2c2.21 0 4-1.79 4-4s-1.79-4-4-4z"/></svg></button><button class="MuiButtonBase-root MuiIconButton-root MuiIconButton-sizeSmall css-fxo539" tabindex="0" type="button" aria-label="copy"><svg class="MuiSvgIcon-root MuiSvgIcon-fontSizeInherit css-1cw4hi4" focusable="false" aria-hidden="true" viewbox="0 0 24 24" data-testid="ContentCopyIcon"><path d="M16 1H4c-1.1 0-2 .9-2 2v14h2V3h12V1zm3 4H8c-1.1 0-2 .9-2 2v14c0 1.1.9 2 2 2h11c1.1 0 2-.9 2-2V7c0-1.1-.9-2-2-2zm0 16H8V7h11v14z"/></svg></button></code></pre><p>根据定义，主键也是唯一键，下面两个建表语句是无效的：</p><pre><code class="hljs language-sql"><div class="MuiBox-root css-1qhimia"><span class="hljs-keyword">CREATE</span> <span class="hljs-keyword">TABLE</span> t5 ( col1 <span class="hljs-type">INT</span> <span class="hljs-keyword">NOT</span> <span class="hljs-keyword">NULL</span>, col2 <span class="hljs-type">DATE</span> <span class="hljs-keyword">NOT</span> <span class="hljs-keyword">NULL</span>, col3 <span class="hljs-type">INT</span> <span class="hljs-keyword">NOT</span> <span class="hljs-keyword">NULL</span>, col4 <span class="hljs-type">INT</span> <span class="hljs-keyword">NOT</span> <span class="hljs-keyword">NULL</span>, <span class="hljs-keyword">PRIMARY</span> KEY(col1, col2) <span class="hljs-keyword">PARTITION</span> <span class="hljs-keyword">BY</span> HASH(col3) PARTITIONS <span class="hljs-number">4</span>; <span class="hljs-keyword">CREATE</span> <span class="hljs-keyword">TABLE</span> t6 ( col1 <span class="hljs-type">INT</span> <span class="hljs-keyword">NOT</span> <span class="hljs-keyword">NULL</span>, col2 <span class="hljs-type">DATE</span> <span class="hljs-keyword">NOT</span> <span class="hljs-keyword">NULL</span>, col3 <span class="hljs-type">INT</span> <span class="hljs-keyword">NOT</span> <span class="hljs-keyword">NULL</span>, col4 <span class="hljs-type">INT</span> <span class="hljs-keyword">NOT</span> <span class="hljs-keyword">NULL</span>, <span class="hljs-keyword">PRIMARY</span> KEY(col1, col3), <span class="hljs-keyword">UNIQUE</span> KEY(col2) <span class="hljs-keyword">PARTITION</span> <span class="hljs-keyword">BY</span> HASH( <span class="hljs-keyword">YEAR</span>(col2) ) PARTITIONS <span class="hljs-number">4</span>; </div><button class="MuiButtonBase-root MuiIconButton-root MuiIconButton-sizeSmall css-1rmx1rm" tabindex="0" type="button" aria-label="Toggle code wrap"><svg class="MuiSvgIcon-root MuiSvgIcon-fontSizeInherit css-1cw4hi4" focusable="false" aria-hidden="true" viewbox="0 0 24 24" data-testid="WrapTextIcon"><path d="M4 19h6v-2H4v2zM20 5H4v2h16V5zm-3 6H4v2h13.25c1.1 0 2 .9 2 2s-.9 2-2 2H15v-2l-3 3 3 3v-2h2c2.21 0 4-1.79 4-4s-1.79-4-4-4z"/></svg></button><button class="MuiButtonBase-root MuiIconButton-root MuiIconButton-sizeSmall css-fxo539" tabindex="0" type="button" aria-label="copy"><svg class="MuiSvgIcon-root MuiSvgIcon-fontSizeInherit css-1cw4hi4" focusable="false" aria-hidden="true" viewbox="0 0 24 24" data-testid="ContentCopyIcon"><path d="M16 1H4c-1.1 0-2 .9-2 2v14h2V3h12V1zm3 4H8c-1.1 0-2 .9-2 2v14c0 1.1.9 2 2 2h11c1.1 0 2-.9 2-2V7c0-1.1-.9-2-2-2zm0 16H8V7h11v14z"/></svg></button></code></pre><p>以上两个例子中，主键都没有包含分区表达式中的全部的列，在主键中补充缺失列后语句即为合法：</p><pre><code class="hljs language-sql"><div class="MuiBox-root css-1qhimia"><span class="hljs-keyword">CREATE</span> <span class="hljs-keyword">TABLE</span> t5 ( col1 <span class="hljs-type">INT</span> <span class="hljs-keyword">NOT</span> <span class="hljs-keyword">NULL</span>, col2 <span class="hljs-type">DATE</span> <span class="hljs-keyword">NOT</span> <span class="hljs-keyword">NULL</span>, col3 <span class="hljs-type">INT</span> <span class="hljs-keyword">NOT</span> <span class="hljs-keyword">NULL</span>, col4 <span class="hljs-type">INT</span> <span class="hljs-keyword">NOT</span> <span class="hljs-keyword">NULL</span>, <span class="hljs-keyword">PRIMARY</span> KEY(col1, col2, col3) <span class="hljs-keyword">PARTITION</span> <span class="hljs-keyword">BY</span> HASH(col3) PARTITIONS <span class="hljs-number">4</span>; <span class="hljs-keyword">CREATE</span> <span class="hljs-keyword">TABLE</span> t6 ( col1 <span class="hljs-type">INT</span> <span class="hljs-keyword">NOT</span> <span class="hljs-keyword">NULL</span>, col2 <span class="hljs-type">DATE</span> <span class="hljs-keyword">NOT</span> <span class="hljs-keyword">NULL</span>, col3 <span class="hljs-type">INT</span> <span class="hljs-keyword">NOT</span> <span class="hljs-keyword">NULL</span>, col4 <span class="hljs-type">INT</span> <span class="hljs-keyword">NOT</span> <span class="hljs-keyword">NULL</span>, <span class="hljs-keyword">PRIMARY</span> KEY(col1, col2, col3), <span class="hljs-keyword">UNIQUE</span> KEY(col2) <span class="hljs-keyword">PARTITION</span> <span class="hljs-keyword">BY</span> HASH( <span class="hljs-keyword">YEAR</span>(col2) ) PARTITIONS <span class="hljs-number">4</span>; </div><button class="MuiButtonBase-root MuiIconButton-root MuiIconButton-sizeSmall css-1rmx1rm" tabindex="0" type="button" aria-label="Toggle code wrap"><svg class="MuiSvgIcon-root MuiSvgIcon-fontSizeInherit css-1cw4hi4" focusable="false" aria-hidden="true" viewbox="0 0 24 24" data-testid="WrapTextIcon"><path d="M4 19h6v-2H4v2zM20 5H4v2h16V5zm-3 6H4v2h13.25c1.1 0 2 .9 2 2s-.9 2-2 2H15v-2l-3 3 3 3v-2h2c2.21 0 4-1.79 4-4s-1.79-4-4-4z"/></svg></button><button class="MuiButtonBase-root MuiIconButton-root MuiIconButton-sizeSmall css-fxo539" tabindex="0" type="button" aria-label="copy"><svg class="MuiSvgIcon-root MuiSvgIcon-fontSizeInherit css-1cw4hi4" focusable="false" aria-hidden="true" viewbox="0 0 24 24" data-testid="ContentCopyIcon"><path d="M16 1H4c-1.1 0-2 .9-2 2v14h2V3h12V1zm3 4H8c-1.1 0-2 .9-2 2v14c0 1.1.9 2 2 2h11c1.1 0 2-.9 2-2V7c0-1.1-.9-2-2-2zm0 16H8V7h11v14z"/></svg></button></code></pre><p>如果既没有主键，也没有唯一键，则不存在这个限制。</p><p>DDL 变更时，添加唯一索引也需要考虑到这个限制。比如创建了这样一个表：</p><pre><code class="hljs language-sql"><div class="MuiBox-root css-1qhimia"><span class="hljs-keyword">CREATE</span> <span class="hljs-keyword">TABLE</span> t_no_pk (c1 <span class="hljs-type">INT</span>, c2 <span class="hljs-type">INT</span>) <span class="hljs-keyword">PARTITION</span> <span class="hljs-keyword">BY</span> <span class="hljs-keyword">RANGE</span>(c1) ( <span class="hljs-keyword">PARTITION</span> p0 <span class="hljs-keyword">VALUES</span> LESS THAN (<span class="hljs-number">10</span>), <span class="hljs-keyword">PARTITION</span> p1 <span class="hljs-keyword">VALUES</span> LESS THAN (<span class="hljs-number">20</span>), <span class="hljs-keyword">PARTITION</span> p2 <span class="hljs-keyword">VALUES</span> LESS THAN (<span class="hljs-number">30</span>), <span class="hljs-keyword">PARTITION</span> p3 <span class="hljs-keyword">VALUES</span> LESS THAN (<span class="hljs-number">40</span>) </div><button class="MuiButtonBase-root MuiIconButton-root MuiIconButton-sizeSmall css-1rmx1rm" tabindex="0" type="button" aria-label="Toggle code wrap"><svg class="MuiSvgIcon-root MuiSvgIcon-fontSizeInherit css-1cw4hi4" focusable="false" aria-hidden="true" viewbox="0 0 24 24" data-testid="WrapTextIcon"><path d="M4 19h6v-2H4v2zM20 5H4v2h16V5zm-3 6H4v2h13.25c1.1 0 2 .9 2 2s-.9 2-2 2H15v-2l-3 3 3 3v-2h2c2.21 0 4-1.79 4-4s-1.79-4-4-4z"/></svg></button><button class="MuiButtonBase-root MuiIconButton-root MuiIconButton-sizeSmall css-fxo539" tabindex="0" type="button" aria-label="copy"><svg class="MuiSvgIcon-root MuiSvgIcon-fontSizeInherit css-1cw4hi4" focusable="false" aria-hidden="true" viewbox="0 0 24 24" data-testid="ContentCopyIcon"><path d="M16 1H4c-1.1 0-2 .9-2 2v14h2V3h12V1zm3 4H8c-1.1 0-2 .9-2 2v14c0 1.1.9 2 2 2h11c1.1 0 2-.9 2-2V7c0-1.1-.9-2-2-2zm0 16H8V7h11v14z"/></svg></button></code></pre><pre><code class="hljs language-"><div class="MuiBox-root css-1qhimia">Query OK, 0 rows affected (0.12 sec) </div><button class="MuiButtonBase-root MuiIconButton-root MuiIconButton-sizeSmall css-1rmx1rm" tabindex="0" type="button" aria-label="Toggle code wrap"><svg class="MuiSvgIcon-root MuiSvgIcon-fontSizeInherit css-1cw4hi4" focusable="false" aria-hidden="true" viewbox="0 0 24 24" data-testid="WrapTextIcon"><path d="M4 19h6v-2H4v2zM20 5H4v2h16V5zm-3 6H4v2h13.25c1.1 0 2 .9 2 2s-.9 2-2 2H15v-2l-3 3 3 3v-2h2c2.21 0 4-1.79 4-4s-1.79-4-4-4z"/></svg></button><button class="MuiButtonBase-root MuiIconButton-root MuiIconButton-sizeSmall css-fxo539" tabindex="0" type="button" aria-label="copy"><svg class="MuiSvgIcon-root MuiSvgIcon-fontSizeInherit css-1cw4hi4" focusable="false" aria-hidden="true" viewbox="0 0 24 24" data-testid="ContentCopyIcon"><path d="M16 1H4c-1.1 0-2 .9-2 2v14h2V3h12V1zm3 4H8c-1.1 0-2 .9-2 2v14c0 1.1.9 2 2 2h11c1.1 0 2-.9 2-2V7c0-1.1-.9-2-2-2zm0 16H8V7h11v14z"/></svg></button></code></pre><p>通过 <code>ALTER TABLE</code> 添加非唯一索引是可以的。但是添加唯一索引时，唯一索引里面必须包含 <code>c1</code> 列。</p><p>使用分区表时，前缀索引是不能指定为唯一属性的：</p><pre><code class="hljs language-sql"><div class="MuiBox-root css-1qhimia"><span class="hljs-keyword">CREATE</span> <span class="hljs-keyword">TABLE</span> t (a <span class="hljs-type">varchar</span>(<span class="hljs-number">20</span>), b <span class="hljs-type">blob</span>, <span class="hljs-keyword">UNIQUE</span> INDEX (a(<span class="hljs-number">5</span>))) <span class="hljs-keyword">PARTITION</span> <span class="hljs-keyword">by</span> <span class="hljs-keyword">range</span> columns (a) ( <span class="hljs-keyword">PARTITION</span> p0 <span class="hljs-keyword">values</span> less than (<span class="hljs-string">'aaaaa'</span>), <span class="hljs-keyword">PARTITION</span> p1 <span class="hljs-keyword">values</span> less than (<span class="hljs-string">'bbbbb'</span>), <span class="hljs-keyword">PARTITION</span> p2 <span class="hljs-keyword">values</span> less than (<span class="hljs-string">'ccccc'</span>)); </div><button class="MuiButtonBase-root MuiIconButton-root MuiIconButton-sizeSmall css-1rmx1rm" tabindex="0" type="button" aria-label="Toggle code wrap"><svg class="MuiSvgIcon-root MuiSvgIcon-fontSizeInherit css-1cw4hi4" focusable="false" aria-hidden="true" viewbox="0 0 24 24" data-testid="WrapTextIcon"><path d="M4 19h6v-2H4v2zM20 5H4v2h16V5zm-3 6H4v2h13.25c1.1 0 2 .9 2 2s-.9 2-2 2H15v-2l-3 3 3 3v-2h2c2.21 0 4-1.79 4-4s-1.79-4-4-4z"/></svg></button><button class="MuiButtonBase-root MuiIconButton-root MuiIconButton-sizeSmall css-fxo539" tabindex="0" type="button" aria-label="copy"><svg class="MuiSvgIcon-root MuiSvgIcon-fontSizeInherit css-1cw4hi4" focusable="false" aria-hidden="true" viewbox="0 0 24 24" data-testid="ContentCopyIcon"><path d="M16 1H4c-1.1 0-2 .9-2 2v14h2V3h12V1zm3 4H8c-1.1 0-2 .9-2 2v14c0 1.1.9 2 2 2h11c1.1 0 2-.9 2-2V7c0-1.1-.9-2-2-2zm0 16H8V7h11v14z"/></svg></button></code></pre><pre><code class="hljs language-sql"><div class="MuiBox-root css-1qhimia">ERROR <span class="hljs-number">1503</span> (HY000): A <span class="hljs-keyword">UNIQUE</span> INDEX must include <span class="hljs-keyword">all</span> columns <span class="hljs-keyword">in</span> the <span class="hljs-keyword">table</span><span class="hljs-string">'s partitioning function </span></div><button class="MuiButtonBase-root MuiIconButton-root MuiIconButton-sizeSmall css-1rmx1rm" tabindex="0" type="button" aria-label="Toggle code wrap"><svg class="MuiSvgIcon-root MuiSvgIcon-fontSizeInherit css-1cw4hi4" focusable="false" aria-hidden="true" viewbox="0 0 24 24" data-testid="WrapTextIcon"><path d="M4 19h6v-2H4v2zM20 5H4v2h16V5zm-3 6H4v2h13.25c1.1 0 2 .9 2 2s-.9 2-2 2H15v-2l-3 3 3 3v-2h2c2.21 0 4-1.79 4-4s-1.79-4-4-4z"/></svg></button><button class="MuiButtonBase-root MuiIconButton-root MuiIconButton-sizeSmall css-fxo539" tabindex="0" type="button" aria-label="copy"><svg class="MuiSvgIcon-root MuiSvgIcon-fontSizeInherit css-1cw4hi4" focusable="false" aria-hidden="true" viewbox="0 0 24 24" data-testid="ContentCopyIcon"><path d="M16 1H4c-1.1 0-2 .9-2 2v14h2V3h12V1zm3 4H8c-1.1 0-2 .9-2 2v14c0 1.1.9 2 2 2h11c1.1 0 2-.9 2-2V7c0-1.1-.9-2-2-2zm0 16H8V7h11v14z"/></svg></button></code></pre><h3 id="关于函数的分区限制" style="position:relative"><a href="#%E5%85%B3%E4%BA%8E%E5%87%BD%E6%95%B0%E7%9A%84%E5%88%86%E5%8C%BA%E9%99%90%E5%88%B6" aria-label="关于函数的分区限制 permalink" class="anchor before"><svg aria-hidden="true" focusable="false" height="16" version="1.1" viewbox="0 0 16 16" width="16"><path fill-rule="evenodd" d="M4 9h1v1H4c-1.5 0-3-1.69-3-3.5S2.55 3 4 3h4c1.45 0 3 1.69 3 3.5 0 1.41-.91 2.72-2 3.25V8.59c.58-.45 1-1.27 1-2.09C10 5.22 8.98 4 8 4H4c-.98 0-2 1.22-2 2.5S3 9 4 9zm9-3h-1v1h1c1 0 2 1.22 2 2.5S13.98 12 13 12H9c-.98 0-2-1.22-2-2.5 0-.83.42-1.64 1-2.09V6.25c-1.09.53-2 1.84-2 3.25C6 11.31 7.55 13 9 13h4c1.45 0 3-1.69 3-3.5S14.5 6 13 6z"/></svg></a>关于函数的分区限制</h3><p>只有以下函数可以用于分区表达式：</p><pre><code class="hljs language-"><div class="MuiBox-root css-1qhimia">ABS() CEILING() DATEDIFF() DAY() DAYOFMONTH() DAYOFWEEK() DAYOFYEAR() EXTRACT() (see EXTRACT() function with WEEK specifier) FLOOR() HOUR() MICROSECOND() MINUTE() MOD() MONTH() QUARTER() SECOND() TIME_TO_SEC() TO_DAYS() TO_SECONDS() UNIX_TIMESTAMP() (with TIMESTAMP columns) WEEKDAY() YEAR() YEARWEEK() </div><button class="MuiButtonBase-root MuiIconButton-root MuiIconButton-sizeSmall css-1rmx1rm" tabindex="0" type="button" aria-label="Toggle code wrap"><svg class="MuiSvgIcon-root MuiSvgIcon-fontSizeInherit css-1cw4hi4" focusable="false" aria-hidden="true" viewbox="0 0 24 24" data-testid="WrapTextIcon"><path d="M4 19h6v-2H4v2zM20 5H4v2h16V5zm-3 6H4v2h13.25c1.1 0 2 .9 2 2s-.9 2-2 2H15v-2l-3 3 3 3v-2h2c2.21 0 4-1.79 4-4s-1.79-4-4-4z"/></svg></button><button class="MuiButtonBase-root MuiIconButton-root MuiIconButton-sizeSmall css-fxo539" tabindex="0" type="button" aria-label="copy"><svg class="MuiSvgIcon-root MuiSvgIcon-fontSizeInherit css-1cw4hi4" focusable="false" aria-hidden="true" viewbox="0 0 24 24" data-testid="ContentCopyIcon"><path d="M16 1H4c-1.1 0-2 .9-2 2v14h2V3h12V1zm3 4H8c-1.1 0-2 .9-2 2v14c0 1.1.9 2 2 2h11c1.1 0 2-.9 2-2V7c0-1.1-.9-2-2-2zm0 16H8V7h11v14z"/></svg></button></code></pre><h3 id="兼容性" style="position:relative"><a href="#%E5%85%BC%E5%AE%B9%E6%80%A7" aria-label="兼容性 permalink" class="anchor before"><svg aria-hidden="true" focusable="false" height="16" version="1.1" viewbox="0 0 16 16" width="16"><path fill-rule="evenodd" d="M4 9h1v1H4c-1.5 0-3-1.69-3-3.5S2.55 3 4 3h4c1.45 0 3 1.69 3 3.5 0 1.41-.91 2.72-2 3.25V8.59c.58-.45 1-1.27 1-2.09C10 5.22 8.98 4 8 4H4c-.98 0-2 1.22-2 2.5S3 9 4 9zm9-3h-1v1h1c1 0 2 1.22 2 2.5S13.98 12 13 12H9c-.98 0-2-1.22-2-2.5 0-.83.42-1.64 1-2.09V6.25c-1.09.53-2 1.84-2 3.25C6 11.31 7.55 13 9 13h4c1.45 0 3-1.69 3-3.5S14.5 6 13 6z"/></svg></a>兼容性</h3><p>目前 TiDB 支持 Range 分区、Range Columns 分区、List 分区、List COLUMNS 分区、Hash 分区和 Key 分区，其它的 MySQL 分区类型尚不支持。</p><p>对于 Key 分区，目前不支持分区字段为空的场景。</p><p>分区管理方面，只要底层实现可能会涉及数据挪动的操作，目前都暂不支持。包括且不限于：调整 Hash 分区表的分区数量，修改 Range 分区表的范围，合并分区等。</p><p>对于暂不支持的分区类型，在 TiDB 中建表时会忽略分区信息，以普通表的形式创建，并且会报 Warning。</p><p>Load Data 暂时不支持分区选择。</p><pre><code class="hljs language-sql"><div class="MuiBox-root css-1qhimia"><span class="hljs-keyword">create</span> <span class="hljs-keyword">table</span> t (id <span class="hljs-type">int</span>, val <span class="hljs-type">int</span>) <span class="hljs-keyword">partition</span> <span class="hljs-keyword">by</span> hash(id) partitions <span class="hljs-number">4</span>; </div><button class="MuiButtonBase-root MuiIconButton-root MuiIconButton-sizeSmall css-1rmx1rm" tabindex="0" type="button" aria-label="Toggle code wrap"><svg class="MuiSvgIcon-root MuiSvgIcon-fontSizeInherit css-1cw4hi4" focusable="false" aria-hidden="true" viewbox="0 0 24 24" data-testid="WrapTextIcon"><path d="M4 19h6v-2H4v2zM20 5H4v2h16V5zm-3 6H4v2h13.25c1.1 0 2 .9 2 2s-.9 2-2 2H15v-2l-3 3 3 3v-2h2c2.21 0 4-1.79 4-4s-1.79-4-4-4z"/></svg></button><button class="MuiButtonBase-root MuiIconButton-root MuiIconButton-sizeSmall css-fxo539" tabindex="0" type="button" aria-label="copy"><svg class="MuiSvgIcon-root MuiSvgIcon-fontSizeInherit css-1cw4hi4" focusable="false" aria-hidden="true" viewbox="0 0 24 24" data-testid="ContentCopyIcon"><path d="M16 1H4c-1.1 0-2 .9-2 2v14h2V3h12V1zm3 4H8c-1.1 0-2 .9-2 2v14c0 1.1.9 2 2 2h11c1.1 0 2-.9 2-2V7c0-1.1-.9-2-2-2zm0 16H8V7h11v14z"/></svg></button></code></pre><p>普通的 Load Data 操作在 TiDB 中是支持的，如下：</p><pre><code class="hljs language-sql"><div class="MuiBox-root css-1qhimia">load <span class="hljs-keyword">local</span> data infile "xxx" <span class="hljs-keyword">into</span> t ... </div><button class="MuiButtonBase-root MuiIconButton-root MuiIconButton-sizeSmall css-1rmx1rm" tabindex="0" type="button" aria-label="Toggle code wrap"><svg class="MuiSvgIcon-root MuiSvgIcon-fontSizeInherit css-1cw4hi4" focusable="false" aria-hidden="true" viewbox="0 0 24 24" data-testid="WrapTextIcon"><path d="M4 19h6v-2H4v2zM20 5H4v2h16V5zm-3 6H4v2h13.25c1.1 0 2 .9 2 2s-.9 2-2 2H15v-2l-3 3 3 3v-2h2c2.21 0 4-1.79 4-4s-1.79-4-4-4z"/></svg></button><button class="MuiButtonBase-root MuiIconButton-root MuiIconButton-sizeSmall css-fxo539" tabindex="0" type="button" aria-label="copy"><svg class="MuiSvgIcon-root MuiSvgIcon-fontSizeInherit css-1cw4hi4" focusable="false" aria-hidden="true" viewbox="0 0 24 24" data-testid="ContentCopyIcon"><path d="M16 1H4c-1.1 0-2 .9-2 2v14h2V3h12V1zm3 4H8c-1.1 0-2 .9-2 2v14c0 1.1.9 2 2 2h11c1.1 0 2-.9 2-2V7c0-1.1-.9-2-2-2zm0 16H8V7h11v14z"/></svg></button></code></pre><p>但 Load Data 不支持分区选择操作：</p><pre><code class="hljs language-sql"><div class="MuiBox-root css-1qhimia">load <span class="hljs-keyword">local</span> data infile "xxx" <span class="hljs-keyword">into</span> t <span class="hljs-keyword">partition</span> (p1)... </div><button class="MuiButtonBase-root MuiIconButton-root MuiIconButton-sizeSmall css-1rmx1rm" tabindex="0" type="button" aria-label="Toggle code wrap"><svg class="MuiSvgIcon-root MuiSvgIcon-fontSizeInherit css-1cw4hi4" focusable="false" aria-hidden="true" viewbox="0 0 24 24" data-testid="WrapTextIcon"><path d="M4 19h6v-2H4v2zM20 5H4v2h16V5zm-3 6H4v2h13.25c1.1 0 2 .9 2 2s-.9 2-2 2H15v-2l-3 3 3 3v-2h2c2.21 0 4-1.79 4-4s-1.79-4-4-4z"/></svg></button><button class="MuiButtonBase-root MuiIconButton-root MuiIconButton-sizeSmall css-fxo539" tabindex="0" type="button" aria-label="copy"><svg class="MuiSvgIcon-root MuiSvgIcon-fontSizeInherit css-1cw4hi4" focusable="false" aria-hidden="true" viewbox="0 0 24 24" data-testid="ContentCopyIcon"><path d="M16 1H4c-1.1 0-2 .9-2 2v14h2V3h12V1zm3 4H8c-1.1 0-2 .9-2 2v14c0 1.1.9 2 2 2h11c1.1 0 2-.9 2-2V7c0-1.1-.9-2-2-2zm0 16H8V7h11v14z"/></svg></button></code></pre><p>对于分区表，<code>select * from t</code> 的返回结果是分区之间无序的。这跟 MySQL 不同，MySQL 的返回结果是分区之间有序，分区内部无序。</p><pre><code class="hljs language-sql"><div class="MuiBox-root css-1qhimia"><span class="hljs-keyword">create</span> <span class="hljs-keyword">table</span> t (id <span class="hljs-type">int</span>, val <span class="hljs-type">int</span>) <span class="hljs-keyword">partition</span> <span class="hljs-keyword">by</span> <span class="hljs-keyword">range</span> (id) ( <span class="hljs-keyword">partition</span> p0 <span class="hljs-keyword">values</span> less than (<span class="hljs-number">3</span>), <span class="hljs-keyword">partition</span> p1 <span class="hljs-keyword">values</span> less than (<span class="hljs-number">7</span>), <span class="hljs-keyword">partition</span> p2 <span class="hljs-keyword">values</span> less than (<span class="hljs-number">11</span>)); </div><button class="MuiButtonBase-root MuiIconButton-root MuiIconButton-sizeSmall css-1rmx1rm" tabindex="0" type="button" aria-label="Toggle code wrap"><svg class="MuiSvgIcon-root MuiSvgIcon-fontSizeInherit css-1cw4hi4" focusable="false" aria-hidden="true" viewbox="0 0 24 24" data-testid="WrapTextIcon"><path d="M4 19h6v-2H4v2zM20 5H4v2h16V5zm-3 6H4v2h13.25c1.1 0 2 .9 2 2s-.9 2-2 2H15v-2l-3 3 3 3v-2h2c2.21 0 4-1.79 4-4s-1.79-4-4-4z"/></svg></button><button class="MuiButtonBase-root MuiIconButton-root MuiIconButton-sizeSmall css-fxo539" tabindex="0" type="button" aria-label="copy"><svg class="MuiSvgIcon-root MuiSvgIcon-fontSizeInherit css-1cw4hi4" focusable="false" aria-hidden="true" viewbox="0 0 24 24" data-testid="ContentCopyIcon"><path d="M16 1H4c-1.1 0-2 .9-2 2v14h2V3h12V1zm3 4H8c-1.1 0-2 .9-2 2v14c0 1.1.9 2 2 2h11c1.1 0 2-.9 2-2V7c0-1.1-.9-2-2-2zm0 16H8V7h11v14z"/></svg></button></code></pre><pre><code class="hljs language-"><div class="MuiBox-root css-1qhimia">Query OK, 0 rows affected (0.10 sec) </div><button class="MuiButtonBase-root MuiIconButton-root MuiIconButton-sizeSmall css-1rmx1rm" tabindex="0" type="button" aria-label="Toggle code wrap"><svg class="MuiSvgIcon-root MuiSvgIcon-fontSizeInherit css-1cw4hi4" focusable="false" aria-hidden="true" viewbox="0 0 24 24" data-testid="WrapTextIcon"><path d="M4 19h6v-2H4v2zM20 5H4v2h16V5zm-3 6H4v2h13.25c1.1 0 2 .9 2 2s-.9 2-2 2H15v-2l-3 3 3 3v-2h2c2.21 0 4-1.79 4-4s-1.79-4-4-4z"/></svg></button><button class="MuiButtonBase-root MuiIconButton-root MuiIconButton-sizeSmall css-fxo539" tabindex="0" type="button" aria-label="copy"><svg class="MuiSvgIcon-root MuiSvgIcon-fontSizeInherit css-1cw4hi4" focusable="false" aria-hidden="true" viewbox="0 0 24 24" data-testid="ContentCopyIcon"><path d="M16 1H4c-1.1 0-2 .9-2 2v14h2V3h12V1zm3 4H8c-1.1 0-2 .9-2 2v14c0 1.1.9 2 2 2h11c1.1 0 2-.9 2-2V7c0-1.1-.9-2-2-2zm0 16H8V7h11v14z"/></svg></button></code></pre><pre><code class="hljs language-sql"><div class="MuiBox-root css-1qhimia"><span class="hljs-keyword">insert</span> <span class="hljs-keyword">into</span> t <span class="hljs-keyword">values</span> (<span class="hljs-number">1</span>, <span class="hljs-number">2</span>), (<span class="hljs-number">3</span>, <span class="hljs-number">4</span>),(<span class="hljs-number">5</span>, <span class="hljs-number">6</span>),(<span class="hljs-number">7</span>,<span class="hljs-number">8</span>),(<span class="hljs-number">9</span>,<span class="hljs-number">10</span>); </div><button class="MuiButtonBase-root MuiIconButton-root MuiIconButton-sizeSmall css-1rmx1rm" tabindex="0" type="button" aria-label="Toggle code wrap"><svg class="MuiSvgIcon-root MuiSvgIcon-fontSizeInherit css-1cw4hi4" focusable="false" aria-hidden="true" viewbox="0 0 24 24" data-testid="WrapTextIcon"><path d="M4 19h6v-2H4v2zM20 5H4v2h16V5zm-3 6H4v2h13.25c1.1 0 2 .9 2 2s-.9 2-2 2H15v-2l-3 3 3 3v-2h2c2.21 0 4-1.79 4-4s-1.79-4-4-4z"/></svg></button><button class="MuiButtonBase-root MuiIconButton-root MuiIconButton-sizeSmall css-fxo539" tabindex="0" type="button" aria-label="copy"><svg class="MuiSvgIcon-root MuiSvgIcon-fontSizeInherit css-1cw4hi4" focusable="false" aria-hidden="true" viewbox="0 0 24 24" data-testid="ContentCopyIcon"><path d="M16 1H4c-1.1 0-2 .9-2 2v14h2V3h12V1zm3 4H8c-1.1 0-2 .9-2 2v14c0 1.1.9 2 2 2h11c1.1 0 2-.9 2-2V7c0-1.1-.9-2-2-2zm0 16H8V7h11v14z"/></svg></button></code></pre><pre><code class="hljs language-"><div class="MuiBox-root css-1qhimia">Query OK, 5 rows affected (0.01 sec) Records: 5 Duplicates: 0 Warnings: 0 </div><button class="MuiButtonBase-root MuiIconButton-root MuiIconButton-sizeSmall css-1rmx1rm" tabindex="0" type="button" aria-label="Toggle code wrap"><svg class="MuiSvgIcon-root MuiSvgIcon-fontSizeInherit css-1cw4hi4" focusable="false" aria-hidden="true" viewbox="0 0 24 24" data-testid="WrapTextIcon"><path d="M4 19h6v-2H4v2zM20 5H4v2h16V5zm-3 6H4v2h13.25c1.1 0 2 .9 2 2s-.9 2-2 2H15v-2l-3 3 3 3v-2h2c2.21 0 4-1.79 4-4s-1.79-4-4-4z"/></svg></button><button class="MuiButtonBase-root MuiIconButton-root MuiIconButton-sizeSmall css-fxo539" tabindex="0" type="button" aria-label="copy"><svg class="MuiSvgIcon-root MuiSvgIcon-fontSizeInherit css-1cw4hi4" focusable="false" aria-hidden="true" viewbox="0 0 24 24" data-testid="ContentCopyIcon"><path d="M16 1H4c-1.1 0-2 .9-2 2v14h2V3h12V1zm3 4H8c-1.1 0-2 .9-2 2v14c0 1.1.9 2 2 2h11c1.1 0 2-.9 2-2V7c0-1.1-.9-2-2-2zm0 16H8V7h11v14z"/></svg></button></code></pre><p>TiDB 每次返回结果会不同，例如：</p><pre><code class="hljs language-"><div class="MuiBox-root css-1qhimia">select * from t; </div><button class="MuiButtonBase-root MuiIconButton-root MuiIconButton-sizeSmall css-1rmx1rm" tabindex="0" type="button" aria-label="Toggle code wrap"><svg class="MuiSvgIcon-root MuiSvgIcon-fontSizeInherit css-1cw4hi4" focusable="false" aria-hidden="true" viewbox="0 0 24 24" data-testid="WrapTextIcon"><path d="M4 19h6v-2H4v2zM20 5H4v2h16V5zm-3 6H4v2h13.25c1.1 0 2 .9 2 2s-.9 2-2 2H15v-2l-3 3 3 3v-2h2c2.21 0 4-1.79 4-4s-1.79-4-4-4z"/></svg></button><button class="MuiButtonBase-root MuiIconButton-root MuiIconButton-sizeSmall css-fxo539" tabindex="0" type="button" aria-label="copy"><svg class="MuiSvgIcon-root MuiSvgIcon-fontSizeInherit css-1cw4hi4" focusable="false" aria-hidden="true" viewbox="0 0 24 24" data-testid="ContentCopyIcon"><path d="M16 1H4c-1.1 0-2 .9-2 2v14h2V3h12V1zm3 4H8c-1.1 0-2 .9-2 2v14c0 1.1.9 2 2 2h11c1.1 0 2-.9 2-2V7c0-1.1-.9-2-2-2zm0 16H8V7h11v14z"/></svg></button></code></pre><pre><code class="hljs language-"><div class="MuiBox-root css-1qhimia">+------|------+ | id | val | +------|------+ | 7 | 8 | | 9 | 10 | | 1 | 2 | | 3 | 4 | | 5 | 6 | +------|------+ 5 rows in set (0.00 sec) </div><button class="MuiButtonBase-root MuiIconButton-root MuiIconButton-sizeSmall css-1rmx1rm" tabindex="0" type="button" aria-label="Toggle code wrap"><svg class="MuiSvgIcon-root MuiSvgIcon-fontSizeInherit css-1cw4hi4" focusable="false" aria-hidden="true" viewbox="0 0 24 24" data-testid="WrapTextIcon"><path d="M4 19h6v-2H4v2zM20 5H4v2h16V5zm-3 6H4v2h13.25c1.1 0 2 .9 2 2s-.9 2-2 2H15v-2l-3 3 3 3v-2h2c2.21 0 4-1.79 4-4s-1.79-4-4-4z"/></svg></button><button class="MuiButtonBase-root MuiIconButton-root MuiIconButton-sizeSmall css-fxo539" tabindex="0" type="button" aria-label="copy"><svg class="MuiSvgIcon-root MuiSvgIcon-fontSizeInherit css-1cw4hi4" focusable="false" aria-hidden="true" viewbox="0 0 24 24" data-testid="ContentCopyIcon"><path d="M16 1H4c-1.1 0-2 .9-2 2v14h2V3h12V1zm3 4H8c-1.1 0-2 .9-2 2v14c0 1.1.9 2 2 2h11c1.1 0 2-.9 2-2V7c0-1.1-.9-2-2-2zm0 16H8V7h11v14z"/></svg></button></code></pre><p>MySQL 的返回结果：</p><pre><code class="hljs language-"><div class="MuiBox-root css-1qhimia">select * from t; </div><button class="MuiButtonBase-root MuiIconButton-root MuiIconButton-sizeSmall css-1rmx1rm" tabindex="0" type="button" aria-label="Toggle code wrap"><svg class="MuiSvgIcon-root MuiSvgIcon-fontSizeInherit css-1cw4hi4" focusable="false" aria-hidden="true" viewbox="0 0 24 24" data-testid="WrapTextIcon"><path d="M4 19h6v-2H4v2zM20 5H4v2h16V5zm-3 6H4v2h13.25c1.1 0 2 .9 2 2s-.9 2-2 2H15v-2l-3 3 3 3v-2h2c2.21 0 4-1.79 4-4s-1.79-4-4-4z"/></svg></button><button class="MuiButtonBase-root MuiIconButton-root MuiIconButton-sizeSmall css-fxo539" tabindex="0" type="button" aria-label="copy"><svg class="MuiSvgIcon-root MuiSvgIcon-fontSizeInherit css-1cw4hi4" focusable="false" aria-hidden="true" viewbox="0 0 24 24" data-testid="ContentCopyIcon"><path d="M16 1H4c-1.1 0-2 .9-2 2v14h2V3h12V1zm3 4H8c-1.1 0-2 .9-2 2v14c0 1.1.9 2 2 2h11c1.1 0 2-.9 2-2V7c0-1.1-.9-2-2-2zm0 16H8V7h11v14z"/></svg></button></code></pre><pre><code class="hljs language-"><div class="MuiBox-root css-1qhimia">+------|------+ | id | val | +------|------+ | 1 | 2 | | 3 | 4 | | 5 | 6 | | 7 | 8 | | 9 | 10 | +------|------+ 5 rows in set (0.00 sec) </div><button class="MuiButtonBase-root MuiIconButton-root MuiIconButton-sizeSmall css-1rmx1rm" tabindex="0" type="button" aria-label="Toggle code wrap"><svg class="MuiSvgIcon-root MuiSvgIcon-fontSizeInherit css-1cw4hi4" focusable="false" aria-hidden="true" viewbox="0 0 24 24" data-testid="WrapTextIcon"><path d="M4 19h6v-2H4v2zM20 5H4v2h16V5zm-3 6H4v2h13.25c1.1 0 2 .9 2 2s-.9 2-2 2H15v-2l-3 3 3 3v-2h2c2.21 0 4-1.79 4-4s-1.79-4-4-4z"/></svg></button><button class="MuiButtonBase-root MuiIconButton-root MuiIconButton-sizeSmall css-fxo539" tabindex="0" type="button" aria-label="copy"><svg class="MuiSvgIcon-root MuiSvgIcon-fontSizeInherit css-1cw4hi4" focusable="false" aria-hidden="true" viewbox="0 0 24 24" data-testid="ContentCopyIcon"><path d="M16 1H4c-1.1 0-2 .9-2 2v14h2V3h12V1zm3 4H8c-1.1 0-2 .9-2 2v14c0 1.1.9 2 2 2h11c1.1 0 2-.9 2-2V7c0-1.1-.9-2-2-2zm0 16H8V7h11v14z"/></svg></button></code></pre><p>环境变量 <code>tidb_enable_list_partition</code> 可以控制是否启用分区表功能。如果该变量设置为 <code>OFF</code>，则建表时会忽略分区信息，以普通表的方式建表。</p><p>该变量仅作用于建表，已经建表之后再修改该变量无效。详见<a href="/zh/tidb/stable/system-variables#tidb_enable_list_partition-从-v50-版本开始引入">系统变量和语法</a>。</p><h3 id="动态裁剪模式" style="position:relative"><a href="#%E5%8A%A8%E6%80%81%E8%A3%81%E5%89%AA%E6%A8%A1%E5%BC%8F" aria-label="动态裁剪模式 permalink" class="anchor before"><svg aria-hidden="true" focusable="false" height="16" version="1.1" viewbox="0 0 16 16" width="16"><path fill-rule="evenodd" d="M4 9h1v1H4c-1.5 0-3-1.69-3-3.5S2.55 3 4 3h4c1.45 0 3 1.69 3 3.5 0 1.41-.91 2.72-2 3.25V8.59c.58-.45 1-1.27 1-2.09C10 5.22 8.98 4 8 4H4c-.98 0-2 1.22-2 2.5S3 9 4 9zm9-3h-1v1h1c1 0 2 1.22 2 2.5S13.98 12 13 12H9c-.98 0-2-1.22-2-2.5 0-.83.42-1.64 1-2.09V6.25c-1.09.53-2 1.84-2 3.25C6 11.31 7.55 13 9 13h4c1.45 0 3-1.69 3-3.5S14.5 6 13 6z"/></svg></a>动态裁剪模式</h3><p>TiDB 访问分区表有两种模式，<code>dynamic</code> 和 <code>static</code>。从 v6.3.0 开始，默认使用 <code>dynamic</code> 模式。但是注意，<code>dynamic</code> 模式仅在表级别汇总统计信息（即 GlobalStats）收集完成的情况下生效。如果选择了 <code>dynamic</code> 但 GlobalStats 未收集完成，TiDB 会仍采用 <code>static</code> 模式。关于 GlobalStats 更多信息，请参考<a href="/zh/tidb/stable/statistics#动态裁剪模式下的分区表统计信息">动态裁剪模式下的分区表统计信息</a>。</p><pre><code class="hljs language-sql"><div class="MuiBox-root css-1qhimia"><span class="hljs-keyword">set</span> @<span class="hljs-variable">@session</span>.tidb_partition_prune_mode <span class="hljs-operator">=</span> <span class="hljs-string">'dynamic'</span> </div><button class="MuiButtonBase-root MuiIconButton-root MuiIconButton-sizeSmall css-1rmx1rm" tabindex="0" type="button" aria-label="Toggle code wrap"><svg class="MuiSvgIcon-root MuiSvgIcon-fontSizeInherit css-1cw4hi4" focusable="false" aria-hidden="true" viewbox="0 0 24 24" data-testid="WrapTextIcon"><path d="M4 19h6v-2H4v2zM20 5H4v2h16V5zm-3 6H4v2h13.25c1.1 0 2 .9 2 2s-.9 2-2 2H15v-2l-3 3 3 3v-2h2c2.21 0 4-1.79 4-4s-1.79-4-4-4z"/></svg></button><button class="MuiButtonBase-root MuiIconButton-root MuiIconButton-sizeSmall css-fxo539" tabindex="0" type="button" aria-label="copy"><svg class="MuiSvgIcon-root MuiSvgIcon-fontSizeInherit css-1cw4hi4" focusable="false" aria-hidden="true" viewbox="0 0 24 24" data-testid="ContentCopyIcon"><path d="M16 1H4c-1.1 0-2 .9-2 2v14h2V3h12V1zm3 4H8c-1.1 0-2 .9-2 2v14c0 1.1.9 2 2 2h11c1.1 0 2-.9 2-2V7c0-1.1-.9-2-2-2zm0 16H8V7h11v14z"/></svg></button></code></pre><p>普通查询和手动 analyze 使用的是 session 级别的 <code>tidb_partition_prune_mode</code> 设置，后台的 auto-analyze 使用的是 global 级别的 <code>tidb_partition_prune_mode</code> 设置。</p><p>静态裁剪模式下，分区表使用的是分区级别的统计信息，而动态裁剪模式下，分区表用的是表级别的汇总统计信息。</p><p>从 <code>static</code> 静态裁剪模式切到 <code>dynamic</code> 动态裁剪模式时，需要手动检查和收集统计信息。在刚切换到 <code>dynamic</code> 时，分区表上仍然只有分区的统计信息，需要等到全局 <code>dynamic</code> 动态裁剪模式开启后的下一次 <code>auto-analyze</code> 周期，才会更新生成汇总统计信息。</p><pre><code class="hljs language-sql"><div class="MuiBox-root css-1qhimia"><span class="hljs-keyword">set</span> session tidb_partition_prune_mode <span class="hljs-operator">=</span> <span class="hljs-string">'dynamic'</span>; <span class="hljs-keyword">show</span> stats_meta <span class="hljs-keyword">where</span> table_name <span class="hljs-keyword">like</span> "t"; </div><button class="MuiButtonBase-root MuiIconButton-root MuiIconButton-sizeSmall css-1rmx1rm" tabindex="0" type="button" aria-label="Toggle code wrap"><svg class="MuiSvgIcon-root MuiSvgIcon-fontSizeInherit css-1cw4hi4" focusable="false" aria-hidden="true" viewbox="0 0 24 24" data-testid="WrapTextIcon"><path d="M4 19h6v-2H4v2zM20 5H4v2h16V5zm-3 6H4v2h13.25c1.1 0 2 .9 2 2s-.9 2-2 2H15v-2l-3 3 3 3v-2h2c2.21 0 4-1.79 4-4s-1.79-4-4-4z"/></svg></button><button class="MuiButtonBase-root MuiIconButton-root MuiIconButton-sizeSmall css-fxo539" tabindex="0" type="button" aria-label="copy"><svg class="MuiSvgIcon-root MuiSvgIcon-fontSizeInherit css-1cw4hi4" focusable="false" aria-hidden="true" viewbox="0 0 24 24" data-testid="ContentCopyIcon"><path d="M16 1H4c-1.1 0-2 .9-2 2v14h2V3h12V1zm3 4H8c-1.1 0-2 .9-2 2v14c0 1.1.9 2 2 2h11c1.1 0 2-.9 2-2V7c0-1.1-.9-2-2-2zm0 16H8V7h11v14z"/></svg></button></code></pre><pre><code class="hljs language-"><div class="MuiBox-root css-1qhimia">+---------+------------+----------------+---------------------+--------------+-----------+ | Db_name | Table_name | Partition_name | Update_time | Modify_count | Row_count | +---------+------------+----------------+---------------------+--------------+-----------+ | test | t | p0 | 2022-05-27 20:23:34 | 1 | 2 | | test | t | p1 | 2022-05-27 20:23:34 | 2 | 4 | | test | t | p2 | 2022-05-27 20:23:34 | 2 | 4 | +---------+------------+----------------+---------------------+--------------+-----------+ 3 rows in set (0.01 sec) </div><button class="MuiButtonBase-root MuiIconButton-root MuiIconButton-sizeSmall css-1rmx1rm" tabindex="0" type="button" aria-label="Toggle code wrap"><svg class="MuiSvgIcon-root MuiSvgIcon-fontSizeInherit css-1cw4hi4" focusable="false" aria-hidden="true" viewbox="0 0 24 24" data-testid="WrapTextIcon"><path d="M4 19h6v-2H4v2zM20 5H4v2h16V5zm-3 6H4v2h13.25c1.1 0 2 .9 2 2s-.9 2-2 2H15v-2l-3 3 3 3v-2h2c2.21 0 4-1.79 4-4s-1.79-4-4-4z"/></svg></button><button class="MuiButtonBase-root MuiIconButton-root MuiIconButton-sizeSmall css-fxo539" tabindex="0" type="button" aria-label="copy"><svg class="MuiSvgIcon-root MuiSvgIcon-fontSizeInherit css-1cw4hi4" focusable="false" aria-hidden="true" viewbox="0 0 24 24" data-testid="ContentCopyIcon"><path d="M16 1H4c-1.1 0-2 .9-2 2v14h2V3h12V1zm3 4H8c-1.1 0-2 .9-2 2v14c0 1.1.9 2 2 2h11c1.1 0 2-.9 2-2V7c0-1.1-.9-2-2-2zm0 16H8V7h11v14z"/></svg></button></code></pre><p>为保证开启全局 <code>dynamic</code> 动态裁剪模式时，SQL 可以用上正确的统计信息，此时需要手动触发一次 <code>analyze</code> 来更新汇总统计信息，可以通过 <code>analyze</code> 表或者单个分区来更新。</p><pre><code class="hljs language-sql"><div class="MuiBox-root css-1qhimia">analyze <span class="hljs-keyword">table</span> t <span class="hljs-keyword">partition</span> p1; <span class="hljs-keyword">show</span> stats_meta <span class="hljs-keyword">where</span> table_name <span class="hljs-keyword">like</span> "t"; </div><button class="MuiButtonBase-root MuiIconButton-root MuiIconButton-sizeSmall css-1rmx1rm" tabindex="0" type="button" aria-label="Toggle code wrap"><svg class="MuiSvgIcon-root MuiSvgIcon-fontSizeInherit css-1cw4hi4" focusable="false" aria-hidden="true" viewbox="0 0 24 24" data-testid="WrapTextIcon"><path d="M4 19h6v-2H4v2zM20 5H4v2h16V5zm-3 6H4v2h13.25c1.1 0 2 .9 2 2s-.9 2-2 2H15v-2l-3 3 3 3v-2h2c2.21 0 4-1.79 4-4s-1.79-4-4-4z"/></svg></button><button class="MuiButtonBase-root MuiIconButton-root MuiIconButton-sizeSmall css-fxo539" tabindex="0" type="button" aria-label="copy"><svg class="MuiSvgIcon-root MuiSvgIcon-fontSizeInherit css-1cw4hi4" focusable="false" aria-hidden="true" viewbox="0 0 24 24" data-testid="ContentCopyIcon"><path d="M16 1H4c-1.1 0-2 .9-2 2v14h2V3h12V1zm3 4H8c-1.1 0-2 .9-2 2v14c0 1.1.9 2 2 2h11c1.1 0 2-.9 2-2V7c0-1.1-.9-2-2-2zm0 16H8V7h11v14z"/></svg></button></code></pre><pre><code class="hljs language-"><div class="MuiBox-root css-1qhimia">+---------+------------+----------------+---------------------+--------------+-----------+ | Db_name | Table_name | Partition_name | Update_time | Modify_count | Row_count | +---------+------------+----------------+---------------------+--------------+-----------+ | test | t | global | 2022-05-27 20:50:53 | 0 | 5 | | test | t | p0 | 2022-05-27 20:23:34 | 1 | 2 | | test | t | p1 | 2022-05-27 20:50:52 | 0 | 2 | | test | t | p2 | 2022-05-27 20:50:08 | 0 | 2 | +---------+------------+----------------+---------------------+--------------+-----------+ 4 rows in set (0.00 sec) </div><button class="MuiButtonBase-root MuiIconButton-root MuiIconButton-sizeSmall css-1rmx1rm" tabindex="0" type="button" aria-label="Toggle code wrap"><svg class="MuiSvgIcon-root MuiSvgIcon-fontSizeInherit css-1cw4hi4" focusable="false" aria-hidden="true" viewbox="0 0 24 24" data-testid="WrapTextIcon"><path d="M4 19h6v-2H4v2zM20 5H4v2h16V5zm-3 6H4v2h13.25c1.1 0 2 .9 2 2s-.9 2-2 2H15v-2l-3 3 3 3v-2h2c2.21 0 4-1.79 4-4s-1.79-4-4-4z"/></svg></button><button class="MuiButtonBase-root MuiIconButton-root MuiIconButton-sizeSmall css-fxo539" tabindex="0" type="button" aria-label="copy"><svg class="MuiSvgIcon-root MuiSvgIcon-fontSizeInherit css-1cw4hi4" focusable="false" aria-hidden="true" viewbox="0 0 24 24" data-testid="ContentCopyIcon"><path d="M16 1H4c-1.1 0-2 .9-2 2v14h2V3h12V1zm3 4H8c-1.1 0-2 .9-2 2v14c0 1.1.9 2 2 2h11c1.1 0 2-.9 2-2V7c0-1.1-.9-2-2-2zm0 16H8V7h11v14z"/></svg></button></code></pre><p>若 analyze 过程中提示如下 warning，说明分区的统计信息之间存在不一致，需要重新收集分区或整个表统计信息。</p><pre><code class="hljs language-"><div class="MuiBox-root css-1qhimia">| Warning | 8244 | Build table: `t` column: `a` global-level stats failed due to missing partition-level column stats, please run analyze table to refresh columns of all partitions </div><button class="MuiButtonBase-root MuiIconButton-root MuiIconButton-sizeSmall css-1rmx1rm" tabindex="0" type="button" aria-label="Toggle code wrap"><svg class="MuiSvgIcon-root MuiSvgIcon-fontSizeInherit css-1cw4hi4" focusable="false" aria-hidden="true" viewbox="0 0 24 24" data-testid="WrapTextIcon"><path d="M4 19h6v-2H4v2zM20 5H4v2h16V5zm-3 6H4v2h13.25c1.1 0 2 .9 2 2s-.9 2-2 2H15v-2l-3 3 3 3v-2h2c2.21 0 4-1.79 4-4s-1.79-4-4-4z"/></svg></button><button class="MuiButtonBase-root MuiIconButton-root MuiIconButton-sizeSmall css-fxo539" tabindex="0" type="button" aria-label="copy"><svg class="MuiSvgIcon-root MuiSvgIcon-fontSizeInherit css-1cw4hi4" focusable="false" aria-hidden="true" viewbox="0 0 24 24" data-testid="ContentCopyIcon"><path d="M16 1H4c-1.1 0-2 .9-2 2v14h2V3h12V1zm3 4H8c-1.1 0-2 .9-2 2v14c0 1.1.9 2 2 2h11c1.1 0 2-.9 2-2V7c0-1.1-.9-2-2-2zm0 16H8V7h11v14z"/></svg></button></code></pre><p>也可以使用脚本来统一更新所有的分区表统计信息，详见<a href="/zh/tidb/stable/partitioned-table#为动态裁剪模式更新所有分区表的统计信息">为动态裁剪模式更新所有分区表的统计信息</a>。</p><p>表级别统计信息准备好后，即可开启全局的动态裁剪模式。全局动态裁剪模式，对全局所有的 SQL 和对后台的统计信息自动收集（即 auto analyze）起作用。</p><pre><code class="hljs language-sql"><div class="MuiBox-root css-1qhimia"><span class="hljs-keyword">set</span> <span class="hljs-keyword">global</span> tidb_partition_prune_mode <span class="hljs-operator">=</span> <span class="hljs-keyword">dynamic</span> </div><button class="MuiButtonBase-root MuiIconButton-root MuiIconButton-sizeSmall css-1rmx1rm" tabindex="0" type="button" aria-label="Toggle code wrap"><svg class="MuiSvgIcon-root MuiSvgIcon-fontSizeInherit css-1cw4hi4" focusable="false" aria-hidden="true" viewbox="0 0 24 24" data-testid="WrapTextIcon"><path d="M4 19h6v-2H4v2zM20 5H4v2h16V5zm-3 6H4v2h13.25c1.1 0 2 .9 2 2s-.9 2-2 2H15v-2l-3 3 3 3v-2h2c2.21 0 4-1.79 4-4s-1.79-4-4-4z"/></svg></button><button class="MuiButtonBase-root MuiIconButton-root MuiIconButton-sizeSmall css-fxo539" tabindex="0" type="button" aria-label="copy"><svg class="MuiSvgIcon-root MuiSvgIcon-fontSizeInherit css-1cw4hi4" focusable="false" aria-hidden="true" viewbox="0 0 24 24" data-testid="ContentCopyIcon"><path d="M16 1H4c-1.1 0-2 .9-2 2v14h2V3h12V1zm3 4H8c-1.1 0-2 .9-2 2v14c0 1.1.9 2 2 2h11c1.1 0 2-.9 2-2V7c0-1.1-.9-2-2-2zm0 16H8V7h11v14z"/></svg></button></code></pre><p>在 <code>static</code> 模式下，TiDB 用多个算子单独访问每个分区，然后通过 Union 将结果合并起来。下面例子进行了一个简单的读取操作，可以发现 TiDB 用 Union 合并了对应两个分区的结果：</p><pre><code class="hljs language-sql"><div class="MuiBox-root css-1qhimia">mysql<span class="hljs-operator">&gt;</span> <span class="hljs-keyword">create</span> <span class="hljs-keyword">table</span> t1(id <span class="hljs-type">int</span>, age <span class="hljs-type">int</span>, key(id)) <span class="hljs-keyword">partition</span> <span class="hljs-keyword">by</span> <span class="hljs-keyword">range</span>(id) ( <span class="hljs-keyword">partition</span> p0 <span class="hljs-keyword">values</span> less than (<span class="hljs-number">100</span>), <span class="hljs-keyword">partition</span> p1 <span class="hljs-keyword">values</span> less than (<span class="hljs-number">200</span>), <span class="hljs-keyword">partition</span> p2 <span class="hljs-keyword">values</span> less than (<span class="hljs-number">300</span>), <span class="hljs-keyword">partition</span> p3 <span class="hljs-keyword">values</span> less than (<span class="hljs-number">400</span>)); Query OK, <span class="hljs-number">0</span> <span class="hljs-keyword">rows</span> affected (<span class="hljs-number">0.01</span> sec) mysql<span class="hljs-operator">&gt;</span> explain <span class="hljs-keyword">select</span> <span class="hljs-operator">*</span> <span class="hljs-keyword">from</span> t1 <span class="hljs-keyword">where</span> id <span class="hljs-operator">&lt;</span> <span class="hljs-number">150</span>; </div><button class="MuiButtonBase-root MuiIconButton-root MuiIconButton-sizeSmall css-1rmx1rm" tabindex="0" type="button" aria-label="Toggle code wrap"><svg class="MuiSvgIcon-root MuiSvgIcon-fontSizeInherit css-1cw4hi4" focusable="false" aria-hidden="true" viewbox="0 0 24 24" data-testid="WrapTextIcon"><path d="M4 19h6v-2H4v2zM20 5H4v2h16V5zm-3 6H4v2h13.25c1.1 0 2 .9 2 2s-.9 2-2 2H15v-2l-3 3 3 3v-2h2c2.21 0 4-1.79 4-4s-1.79-4-4-4z"/></svg></button><button class="MuiButtonBase-root MuiIconButton-root MuiIconButton-sizeSmall css-fxo539" tabindex="0" type="button" aria-label="copy"><svg class="MuiSvgIcon-root MuiSvgIcon-fontSizeInherit css-1cw4hi4" focusable="false" aria-hidden="true" viewbox="0 0 24 24" data-testid="ContentCopyIcon"><path d="M16 1H4c-1.1 0-2 .9-2 2v14h2V3h12V1zm3 4H8c-1.1 0-2 .9-2 2v14c0 1.1.9 2 2 2h11c1.1 0 2-.9 2-2V7c0-1.1-.9-2-2-2zm0 16H8V7h11v14z"/></svg></button></code></pre><pre><code class="hljs language-"><div class="MuiBox-root css-1qhimia">+------------------------------+----------+-----------+------------------------+--------------------------------+ | id | estRows | task | access object | operator info | +------------------------------+----------+-----------+------------------------+--------------------------------+ | PartitionUnion_9 | 6646.67 | root | | | | ├─TableReader_12 | 3323.33 | root | | data:Selection_11 | | │ └─Selection_11 | 3323.33 | cop[tikv] | | lt(test.t1.id, 150) | | │ └─TableFullScan_10 | 10000.00 | cop[tikv] | table:t1, partition:p0 | keep order:false, stats:pseudo | | └─TableReader_18 | 3323.33 | root | | data:Selection_17 | | └─Selection_17 | 3323.33 | cop[tikv] | | lt(test.t1.id, 150) | | └─TableFullScan_16 | 10000.00 | cop[tikv] | table:t1, partition:p1 | keep order:false, stats:pseudo | +------------------------------+----------+-----------+------------------------+--------------------------------+ 7 rows in set (0.00 sec) </div><button class="MuiButtonBase-root MuiIconButton-root MuiIconButton-sizeSmall css-1rmx1rm" tabindex="0" type="button" aria-label="Toggle code wrap"><svg class="MuiSvgIcon-root MuiSvgIcon-fontSizeInherit css-1cw4hi4" focusable="false" aria-hidden="true" viewbox="0 0 24 24" data-testid="WrapTextIcon"><path d="M4 19h6v-2H4v2zM20 5H4v2h16V5zm-3 6H4v2h13.25c1.1 0 2 .9 2 2s-.9 2-2 2H15v-2l-3 3 3 3v-2h2c2.21 0 4-1.79 4-4s-1.79-4-4-4z"/></svg></button><button class="MuiButtonBase-root MuiIconButton-root MuiIconButton-sizeSmall css-fxo539" tabindex="0" type="button" aria-label="copy"><svg class="MuiSvgIcon-root MuiSvgIcon-fontSizeInherit css-1cw4hi4" focusable="false" aria-hidden="true" viewbox="0 0 24 24" data-testid="ContentCopyIcon"><path d="M16 1H4c-1.1 0-2 .9-2 2v14h2V3h12V1zm3 4H8c-1.1 0-2 .9-2 2v14c0 1.1.9 2 2 2h11c1.1 0 2-.9 2-2V7c0-1.1-.9-2-2-2zm0 16H8V7h11v14z"/></svg></button></code></pre><p>在 <code>dynamic</code> 模式下，每个算子都支持直接访问多个分区，所以 TiDB 不再使用 Union。</p><pre><code class="hljs language-sql"><div class="MuiBox-root css-1qhimia">mysql<span class="hljs-operator">&gt;</span> <span class="hljs-keyword">set</span> @<span class="hljs-variable">@session</span>.tidb_partition_prune_mode <span class="hljs-operator">=</span> <span class="hljs-string">'dynamic'</span>; Query OK, <span class="hljs-number">0</span> <span class="hljs-keyword">rows</span> affected (<span class="hljs-number">0.00</span> sec) mysql<span class="hljs-operator">&gt;</span> explain <span class="hljs-keyword">select</span> <span class="hljs-operator">*</span> <span class="hljs-keyword">from</span> t1 <span class="hljs-keyword">where</span> id <span class="hljs-operator">&lt;</span> <span class="hljs-number">150</span>; <span class="hljs-operator">+</span><span class="hljs-comment">-------------------------+----------+-----------+-----------------+--------------------------------+</span> <span class="hljs-operator">|</span> id <span class="hljs-operator">|</span> estRows <span class="hljs-operator">|</span> task <span class="hljs-operator">|</span> access object <span class="hljs-operator">|</span> operator info <span class="hljs-operator">|</span> <span class="hljs-operator">+</span><span class="hljs-comment">-------------------------+----------+-----------+-----------------+--------------------------------+</span> <span class="hljs-operator">|</span> TableReader_7 <span class="hljs-operator">|</span> <span class="hljs-number">3323.33</span> <span class="hljs-operator">|</span> root <span class="hljs-operator">|</span> <span class="hljs-keyword">partition</span>:p0,p1 <span class="hljs-operator">|</span> data:Selection_6 <span class="hljs-operator">|</span> <span class="hljs-operator">|</span> └─Selection_6 <span class="hljs-operator">|</span> <span class="hljs-number">3323.33</span> <span class="hljs-operator">|</span> cop[tikv] <span class="hljs-operator">|</span> <span class="hljs-operator">|</span> lt(test.t1.id, <span class="hljs-number">150</span>) <span class="hljs-operator">|</span> <span class="hljs-operator">|</span> └─TableFullScan_5 <span class="hljs-operator">|</span> <span class="hljs-number">10000.00</span> <span class="hljs-operator">|</span> cop[tikv] <span class="hljs-operator">|</span> <span class="hljs-keyword">table</span>:t1 <span class="hljs-operator">|</span> keep <span class="hljs-keyword">order</span>:<span class="hljs-literal">false</span>, stats:pseudo <span class="hljs-operator">|</span> <span class="hljs-operator">+</span><span class="hljs-comment">-------------------------+----------+-----------+-----------------+--------------------------------+</span> <span class="hljs-number">3</span> <span class="hljs-keyword">rows</span> <span class="hljs-keyword">in</span> <span class="hljs-keyword">set</span> (<span class="hljs-number">0.00</span> sec) </div><button class="MuiButtonBase-root MuiIconButton-root MuiIconButton-sizeSmall css-1rmx1rm" tabindex="0" type="button" aria-label="Toggle code wrap"><svg class="MuiSvgIcon-root MuiSvgIcon-fontSizeInherit css-1cw4hi4" focusable="false" aria-hidden="true" viewbox="0 0 24 24" data-testid="WrapTextIcon"><path d="M4 19h6v-2H4v2zM20 5H4v2h16V5zm-3 6H4v2h13.25c1.1 0 2 .9 2 2s-.9 2-2 2H15v-2l-3 3 3 3v-2h2c2.21 0 4-1.79 4-4s-1.79-4-4-4z"/></svg></button><button class="MuiButtonBase-root MuiIconButton-root MuiIconButton-sizeSmall css-fxo539" tabindex="0" type="button" aria-label="copy"><svg class="MuiSvgIcon-root MuiSvgIcon-fontSizeInherit css-1cw4hi4" focusable="false" aria-hidden="true" viewbox="0 0 24 24" data-testid="ContentCopyIcon"><path d="M16 1H4c-1.1 0-2 .9-2 2v14h2V3h12V1zm3 4H8c-1.1 0-2 .9-2 2v14c0 1.1.9 2 2 2h11c1.1 0 2-.9 2-2V7c0-1.1-.9-2-2-2zm0 16H8V7h11v14z"/></svg></button></code></pre><p>从以上查询结果可知，执行计划中的 Union 消失了，分区裁剪依然生效，且执行计划只访问了 <code>p0</code> 和 <code>p1</code> 两个分区。</p><p><code>dynamic</code> 模式让执行计划更简单清晰，省略 Union 操作可提高执行效率，还可避免 Union 并发管理的问题。此外 <code>dynamic</code> 模式下，执行计划可以使用 IndexJoin 的方式，这在 <code>static</code> 模式下是无法实现的。请看下面的例子：</p><p><strong>示例一</strong>：以下示例在 <code>static</code> 模式下执行计划带 IndexJoin 的查询。</p><pre><code class="hljs language-sql"><div class="MuiBox-root css-1qhimia">mysql<span class="hljs-operator">&gt;</span> <span class="hljs-keyword">create</span> <span class="hljs-keyword">table</span> t1 (id <span class="hljs-type">int</span>, age <span class="hljs-type">int</span>, key(id)) <span class="hljs-keyword">partition</span> <span class="hljs-keyword">by</span> <span class="hljs-keyword">range</span>(id) (<span class="hljs-keyword">partition</span> p0 <span class="hljs-keyword">values</span> less than (<span class="hljs-number">100</span>), <span class="hljs-keyword">partition</span> p1 <span class="hljs-keyword">values</span> less than (<span class="hljs-number">200</span>), <span class="hljs-keyword">partition</span> p2 <span class="hljs-keyword">values</span> less than (<span class="hljs-number">300</span>), <span class="hljs-keyword">partition</span> p3 <span class="hljs-keyword">values</span> less than (<span class="hljs-number">400</span>)); Query OK, <span class="hljs-number">0</span> <span class="hljs-keyword">rows</span> affected (<span class="hljs-number">0</span>,<span class="hljs-number">08</span> sec) mysql<span class="hljs-operator">&gt;</span> <span class="hljs-keyword">create</span> <span class="hljs-keyword">table</span> t2 (id <span class="hljs-type">int</span>, code <span class="hljs-type">int</span>); Query OK, <span class="hljs-number">0</span> <span class="hljs-keyword">rows</span> affected (<span class="hljs-number">0.01</span> sec) mysql<span class="hljs-operator">&gt;</span> <span class="hljs-keyword">set</span> @<span class="hljs-variable">@tidb</span>_partition_prune_mode <span class="hljs-operator">=</span> <span class="hljs-string">'static'</span>; Query OK, <span class="hljs-number">0</span> <span class="hljs-keyword">rows</span> affected (<span class="hljs-number">0.00</span> sec) mysql<span class="hljs-operator">&gt;</span> explain <span class="hljs-keyword">select</span> <span class="hljs-comment">/*+ TIDB_INLJ(t1, t2) */</span> t1.<span class="hljs-operator">*</span> <span class="hljs-keyword">from</span> t1, t2 <span class="hljs-keyword">where</span> t2.code <span class="hljs-operator">=</span> <span class="hljs-number">0</span> <span class="hljs-keyword">and</span> t2.id <span class="hljs-operator">=</span> t1.id; <span class="hljs-operator">+</span><span class="hljs-comment">--------------------------------+----------+-----------+------------------------+------------------------------------------------+</span> <span class="hljs-operator">|</span> id <span class="hljs-operator">|</span> estRows <span class="hljs-operator">|</span> task <span class="hljs-operator">|</span> access object <span class="hljs-operator">|</span> operator info <span class="hljs-operator">|</span> <span class="hljs-operator">+</span><span class="hljs-comment">--------------------------------+----------+-----------+------------------------+------------------------------------------------+</span> <span class="hljs-operator">|</span> HashJoin_13 <span class="hljs-operator">|</span> <span class="hljs-number">12.49</span> <span class="hljs-operator">|</span> root <span class="hljs-operator">|</span> <span class="hljs-operator">|</span> <span class="hljs-keyword">inner</span> <span class="hljs-keyword">join</span>, equal:[eq(test.t1.id, test.t2.id)] <span class="hljs-operator">|</span> <span class="hljs-operator">|</span> ├─TableReader_42(Build) <span class="hljs-operator">|</span> <span class="hljs-number">9.99</span> <span class="hljs-operator">|</span> root <span class="hljs-operator">|</span> <span class="hljs-operator">|</span> data:Selection_41 <span class="hljs-operator">|</span> <span class="hljs-operator">|</span> │ └─Selection_41 <span class="hljs-operator">|</span> <span class="hljs-number">9.99</span> <span class="hljs-operator">|</span> cop[tikv] <span class="hljs-operator">|</span> <span class="hljs-operator">|</span> eq(test.t2.code, <span class="hljs-number">0</span>), <span class="hljs-keyword">not</span>(isnull(test.t2.id)) <span class="hljs-operator">|</span> <span class="hljs-operator">|</span> │ └─TableFullScan_40 <span class="hljs-operator">|</span> <span class="hljs-number">10000.00</span> <span class="hljs-operator">|</span> cop[tikv] <span class="hljs-operator">|</span> <span class="hljs-keyword">table</span>:t2 <span class="hljs-operator">|</span> keep <span class="hljs-keyword">order</span>:<span class="hljs-literal">false</span>, stats:pseudo <span class="hljs-operator">|</span> <span class="hljs-operator">|</span> └─PartitionUnion_15(Probe) <span class="hljs-operator">|</span> <span class="hljs-number">39960.00</span> <span class="hljs-operator">|</span> root <span class="hljs-operator">|</span> <span class="hljs-operator">|</span> <span class="hljs-operator">|</span> <span class="hljs-operator">|</span> ├─TableReader_18 <span class="hljs-operator">|</span> <span class="hljs-number">9990.00</span> <span class="hljs-operator">|</span> root <span class="hljs-operator">|</span> <span class="hljs-operator">|</span> data:Selection_17 <span class="hljs-operator">|</span> <span class="hljs-operator">|</span> │ └─Selection_17 <span class="hljs-operator">|</span> <span class="hljs-number">9990.00</span> <span class="hljs-operator">|</span> cop[tikv] <span class="hljs-operator">|</span> <span class="hljs-operator">|</span> <span class="hljs-keyword">not</span>(isnull(test.t1.id)) <span class="hljs-operator">|</span> <span class="hljs-operator">|</span> │ └─TableFullScan_16 <span class="hljs-operator">|</span> <span class="hljs-number">10000.00</span> <span class="hljs-operator">|</span> cop[tikv] <span class="hljs-operator">|</span> <span class="hljs-keyword">table</span>:t1, <span class="hljs-keyword">partition</span>:p0 <span class="hljs-operator">|</span> keep <span class="hljs-keyword">order</span>:<span class="hljs-literal">false</span>, stats:pseudo <span class="hljs-operator">|</span> <span class="hljs-operator">|</span> ├─TableReader_24 <span class="hljs-operator">|</span> <span class="hljs-number">9990.00</span> <span class="hljs-operator">|</span> root <span class="hljs-operator">|</span> <span class="hljs-operator">|</span> data:Selection_23 <span class="hljs-operator">|</span> <span class="hljs-operator">|</span> │ └─Selection_23 <span class="hljs-operator">|</span> <span class="hljs-number">9990.00</span> <span class="hljs-operator">|</span> cop[tikv] <span class="hljs-operator">|</span> <span class="hljs-operator">|</span> <span class="hljs-keyword">not</span>(isnull(test.t1.id)) <span class="hljs-operator">|</span> <span class="hljs-operator">|</span> │ └─TableFullScan_22 <span class="hljs-operator">|</span> <span class="hljs-number">10000.00</span> <span class="hljs-operator">|</span> cop[tikv] <span class="hljs-operator">|</span> <span class="hljs-keyword">table</span>:t1, <span class="hljs-keyword">partition</span>:p1 <span class="hljs-operator">|</span> keep <span class="hljs-keyword">order</span>:<span class="hljs-literal">false</span>, stats:pseudo <span class="hljs-operator">|</span> <span class="hljs-operator">|</span> ├─TableReader_30 <span class="hljs-operator">|</span> <span class="hljs-number">9990.00</span> <span class="hljs-operator">|</span> root <span class="hljs-operator">|</span> <span class="hljs-operator">|</span> data:Selection_29 <span class="hljs-operator">|</span> <span class="hljs-operator">|</span> │ └─Selection_29 <span class="hljs-operator">|</span> <span class="hljs-number">9990.00</span> <span class="hljs-operator">|</span> cop[tikv] <span class="hljs-operator">|</span> <span class="hljs-operator">|</span> <span class="hljs-keyword">not</span>(isnull(test.t1.id)) <span class="hljs-operator">|</span> <span class="hljs-operator">|</span> │ └─TableFullScan_28 <span class="hljs-operator">|</span> <span class="hljs-number">10000.00</span> <span class="hljs-operator">|</span> cop[tikv] <span class="hljs-operator">|</span> <span class="hljs-keyword">table</span>:t1, <span class="hljs-keyword">partition</span>:p2 <span class="hljs-operator">|</span> keep <span class="hljs-keyword">order</span>:<span class="hljs-literal">false</span>, stats:pseudo <span class="hljs-operator">|</span> <span class="hljs-operator">|</span> └─TableReader_36 <span class="hljs-operator">|</span> <span class="hljs-number">9990.00</span> <span class="hljs-operator">|</span> root <span class="hljs-operator">|</span> <span class="hljs-operator">|</span> data:Selection_35 <span class="hljs-operator">|</span> <span class="hljs-operator">|</span> └─Selection_35 <span class="hljs-operator">|</span> <span class="hljs-number">9990.00</span> <span class="hljs-operator">|</span> cop[tikv] <span class="hljs-operator">|</span> <span class="hljs-operator">|</span> <span class="hljs-keyword">not</span>(isnull(test.t1.id)) <span class="hljs-operator">|</span> <span class="hljs-operator">|</span> └─TableFullScan_34 <span class="hljs-operator">|</span> <span class="hljs-number">10000.00</span> <span class="hljs-operator">|</span> cop[tikv] <span class="hljs-operator">|</span> <span class="hljs-keyword">table</span>:t1, <span class="hljs-keyword">partition</span>:p3 <span class="hljs-operator">|</span> keep <span class="hljs-keyword">order</span>:<span class="hljs-literal">false</span>, stats:pseudo <span class="hljs-operator">|</span> <span class="hljs-operator">+</span><span class="hljs-comment">--------------------------------+----------+-----------+------------------------+------------------------------------------------+</span> <span class="hljs-number">17</span> <span class="hljs-keyword">rows</span> <span class="hljs-keyword">in</span> <span class="hljs-keyword">set</span>, <span class="hljs-number">1</span> warning (<span class="hljs-number">0.00</span> sec) mysql<span class="hljs-operator">&gt;</span> <span class="hljs-keyword">show</span> warnings; <span class="hljs-operator">+</span><span class="hljs-comment">---------+------+------------------------------------------------------------------------------------+</span> <span class="hljs-operator">|</span> Level <span class="hljs-operator">|</span> Code <span class="hljs-operator">|</span> Message <span class="hljs-operator">|</span> <span class="hljs-operator">+</span><span class="hljs-comment">---------+------+------------------------------------------------------------------------------------+</span> <span class="hljs-operator">|</span> Warning <span class="hljs-operator">|</span> <span class="hljs-number">1815</span> <span class="hljs-operator">|</span> Optimizer Hint <span class="hljs-comment">/*+ INL_JOIN(t1, t2) */</span> <span class="hljs-keyword">or</span> <span class="hljs-comment">/*+ TIDB_INLJ(t1, t2) */</span> <span class="hljs-keyword">is</span> inapplicable <span class="hljs-operator">|</span> <span class="hljs-operator">+</span><span class="hljs-comment">---------+------+------------------------------------------------------------------------------------+</span> <span class="hljs-number">1</span> <span class="hljs-type">row</span> <span class="hljs-keyword">in</span> <span class="hljs-keyword">set</span> (<span class="hljs-number">0</span>,<span class="hljs-number">00</span> sec) </div><button class="MuiButtonBase-root MuiIconButton-root MuiIconButton-sizeSmall css-1rmx1rm" tabindex="0" type="button" aria-label="Toggle code wrap"><svg class="MuiSvgIcon-root MuiSvgIcon-fontSizeInherit css-1cw4hi4" focusable="false" aria-hidden="true" viewbox="0 0 24 24" data-testid="WrapTextIcon"><path d="M4 19h6v-2H4v2zM20 5H4v2h16V5zm-3 6H4v2h13.25c1.1 0 2 .9 2 2s-.9 2-2 2H15v-2l-3 3 3 3v-2h2c2.21 0 4-1.79 4-4s-1.79-4-4-4z"/></svg></button><button class="MuiButtonBase-root MuiIconButton-root MuiIconButton-sizeSmall css-fxo539" tabindex="0" type="button" aria-label="copy"><svg class="MuiSvgIcon-root MuiSvgIcon-fontSizeInherit css-1cw4hi4" focusable="false" aria-hidden="true" viewbox="0 0 24 24" data-testid="ContentCopyIcon"><path d="M16 1H4c-1.1 0-2 .9-2 2v14h2V3h12V1zm3 4H8c-1.1 0-2 .9-2 2v14c0 1.1.9 2 2 2h11c1.1 0 2-.9 2-2V7c0-1.1-.9-2-2-2zm0 16H8V7h11v14z"/></svg></button></code></pre><p>从以上示例一结果可知，即使使用了 <code>TIDB_INLJ</code> 的 hint，也无法使得带分区表的查询选上带 IndexJoin 的执行计划。</p><p><strong>示例二</strong>：以下示例在 <code>dynamic</code> 模式下尝试执行计划带 IndexJoin 的查询。</p><pre><code class="hljs language-sql"><div class="MuiBox-root css-1qhimia">mysql<span class="hljs-operator">&gt;</span> <span class="hljs-keyword">set</span> @<span class="hljs-variable">@tidb</span>_partition_prune_mode <span class="hljs-operator">=</span> <span class="hljs-string">'dynamic'</span>; Query OK, <span class="hljs-number">0</span> <span class="hljs-keyword">rows</span> affected (<span class="hljs-number">0.00</span> sec) mysql<span class="hljs-operator">&gt;</span> explain <span class="hljs-keyword">select</span> <span class="hljs-comment">/*+ TIDB_INLJ(t1, t2) */</span> t1.<span class="hljs-operator">*</span> <span class="hljs-keyword">from</span> t1, t2 <span class="hljs-keyword">where</span> t2.code <span class="hljs-operator">=</span> <span class="hljs-number">0</span> <span class="hljs-keyword">and</span> t2.id <span class="hljs-operator">=</span> t1.id; <span class="hljs-operator">+</span><span class="hljs-comment">---------------------------------+----------+-----------+------------------------+---------------------------------------------------------------------------------------------------------------------+</span> <span class="hljs-operator">|</span> id <span class="hljs-operator">|</span> estRows <span class="hljs-operator">|</span> task <span class="hljs-operator">|</span> access object <span class="hljs-operator">|</span> operator info <span class="hljs-operator">|</span> <span class="hljs-operator">+</span><span class="hljs-comment">---------------------------------+----------+-----------+------------------------+---------------------------------------------------------------------------------------------------------------------+</span> <span class="hljs-operator">|</span> IndexJoin_11 <span class="hljs-operator">|</span> <span class="hljs-number">12.49</span> <span class="hljs-operator">|</span> root <span class="hljs-operator">|</span> <span class="hljs-operator">|</span> <span class="hljs-keyword">inner</span> <span class="hljs-keyword">join</span>, <span class="hljs-keyword">inner</span>:IndexLookUp_10, <span class="hljs-keyword">outer</span> key:test.t2.id, <span class="hljs-keyword">inner</span> key:test.t1.id, equal cond:eq(test.t2.id, test.t1.id) <span class="hljs-operator">|</span> <span class="hljs-operator">|</span> ├─TableReader_16(Build) <span class="hljs-operator">|</span> <span class="hljs-number">9.99</span> <span class="hljs-operator">|</span> root <span class="hljs-operator">|</span> <span class="hljs-operator">|</span> data:Selection_15 <span class="hljs-operator">|</span> <span class="hljs-operator">|</span> │ └─Selection_15 <span class="hljs-operator">|</span> <span class="hljs-number">9.99</span> <span class="hljs-operator">|</span> cop[tikv] <span class="hljs-operator">|</span> <span class="hljs-operator">|</span> eq(test.t2.code, <span class="hljs-number">0</span>), <span class="hljs-keyword">not</span>(isnull(test.t2.id)) <span class="hljs-operator">|</span> <span class="hljs-operator">|</span> │ └─TableFullScan_14 <span class="hljs-operator">|</span> <span class="hljs-number">10000.00</span> <span class="hljs-operator">|</span> cop[tikv] <span class="hljs-operator">|</span> <span class="hljs-keyword">table</span>:t2 <span class="hljs-operator">|</span> keep <span class="hljs-keyword">order</span>:<span class="hljs-literal">false</span>, stats:pseudo <span class="hljs-operator">|</span> <span class="hljs-operator">|</span> └─IndexLookUp_10(Probe) <span class="hljs-operator">|</span> <span class="hljs-number">12.49</span> <span class="hljs-operator">|</span> root <span class="hljs-operator">|</span> <span class="hljs-keyword">partition</span>:<span class="hljs-keyword">all</span> <span class="hljs-operator">|</span> <span class="hljs-operator">|</span> <span class="hljs-operator">|</span> ├─Selection_9(Build) <span class="hljs-operator">|</span> <span class="hljs-number">12.49</span> <span class="hljs-operator">|</span> cop[tikv] <span class="hljs-operator">|</span> <span class="hljs-operator">|</span> <span class="hljs-keyword">not</span>(isnull(test.t1.id)) <span class="hljs-operator">|</span> <span class="hljs-operator">|</span> │ └─IndexRangeScan_7 <span class="hljs-operator">|</span> <span class="hljs-number">12.50</span> <span class="hljs-operator">|</span> cop[tikv] <span class="hljs-operator">|</span> <span class="hljs-keyword">table</span>:t1, index:id(id) <span class="hljs-operator">|</span> <span class="hljs-keyword">range</span>: decided <span class="hljs-keyword">by</span> [eq(test.t1.id, test.t2.id)], keep <span class="hljs-keyword">order</span>:<span class="hljs-literal">false</span>, stats:pseudo <span class="hljs-operator">|</span> <span class="hljs-operator">|</span> └─TableRowIDScan_8(Probe) <span class="hljs-operator">|</span> <span class="hljs-number">12.49</span> <span class="hljs-operator">|</span> cop[tikv] <span class="hljs-operator">|</span> <span class="hljs-keyword">table</span>:t1 <span class="hljs-operator">|</span> keep <span class="hljs-keyword">order</span>:<span class="hljs-literal">false</span>, stats:pseudo <span class="hljs-operator">|</span> <span class="hljs-operator">+</span><span class="hljs-comment">---------------------------------+----------+-----------+------------------------+---------------------------------------------------------------------------------------------------------------------+</span> <span class="hljs-number">8</span> <span class="hljs-keyword">rows</span> <span class="hljs-keyword">in</span> <span class="hljs-keyword">set</span> (<span class="hljs-number">0.00</span> sec) </div><button class="MuiButtonBase-root MuiIconButton-root MuiIconButton-sizeSmall css-1rmx1rm" tabindex="0" type="button" aria-label="Toggle code wrap"><svg class="MuiSvgIcon-root MuiSvgIcon-fontSizeInherit css-1cw4hi4" focusable="false" aria-hidden="true" viewbox="0 0 24 24" data-testid="WrapTextIcon"><path d="M4 19h6v-2H4v2zM20 5H4v2h16V5zm-3 6H4v2h13.25c1.1 0 2 .9 2 2s-.9 2-2 2H15v-2l-3 3 3 3v-2h2c2.21 0 4-1.79 4-4s-1.79-4-4-4z"/></svg></button><button class="MuiButtonBase-root MuiIconButton-root MuiIconButton-sizeSmall css-fxo539" tabindex="0" type="button" aria-label="copy"><svg class="MuiSvgIcon-root MuiSvgIcon-fontSizeInherit css-1cw4hi4" focusable="false" aria-hidden="true" viewbox="0 0 24 24" data-testid="ContentCopyIcon"><path d="M16 1H4c-1.1 0-2 .9-2 2v14h2V3h12V1zm3 4H8c-1.1 0-2 .9-2 2v14c0 1.1.9 2 2 2h11c1.1 0 2-.9 2-2V7c0-1.1-.9-2-2-2zm0 16H8V7h11v14z"/></svg></button></code></pre><p>从示例二结果可知，开启 <code>dynamic</code> 模式后，带 IndexJoin 的计划在执行查询时被选上。</p><p>目前，静态和动态裁剪模式都不支持执行计划缓存。</p><h4 id="为动态裁剪模式更新所有分区表的统计信息" style="position:relative"><a href="#%E4%B8%BA%E5%8A%A8%E6%80%81%E8%A3%81%E5%89%AA%E6%A8%A1%E5%BC%8F%E6%9B%B4%E6%96%B0%E6%89%80%E6%9C%89%E5%88%86%E5%8C%BA%E8%A1%A8%E7%9A%84%E7%BB%9F%E8%AE%A1%E4%BF%A1%E6%81%AF" aria-label="为动态裁剪模式更新所有分区表的统计信息 permalink" class="anchor before"><svg aria-hidden="true" focusable="false" height="16" version="1.1" viewbox="0 0 16 16" width="16"><path fill-rule="evenodd" d="M4 9h1v1H4c-1.5 0-3-1.69-3-3.5S2.55 3 4 3h4c1.45 0 3 1.69 3 3.5 0 1.41-.91 2.72-2 3.25V8.59c.58-.45 1-1.27 1-2.09C10 5.22 8.98 4 8 4H4c-.98 0-2 1.22-2 2.5S3 9 4 9zm9-3h-1v1h1c1 0 2 1.22 2 2.5S13.98 12 13 12H9c-.98 0-2-1.22-2-2.5 0-.83.42-1.64 1-2.09V6.25c-1.09.53-2 1.84-2 3.25C6 11.31 7.55 13 9 13h4c1.45 0 3-1.69 3-3.5S14.5 6 13 6z"/></svg></a>为动态裁剪模式更新所有分区表的统计信息</h4><ol><li><p>找到所有的分区表：</p><pre><code class="hljs language-sql"><div class="MuiBox-root css-1qhimia"><span class="hljs-keyword">SELECT</span> <span class="hljs-keyword">DISTINCT</span> CONCAT(TABLE_SCHEMA,<span class="hljs-string">'.'</span>, TABLE_NAME) <span class="hljs-keyword">FROM</span> information_schema.PARTITIONS <span class="hljs-keyword">WHERE</span> TIDB_PARTITION_ID <span class="hljs-keyword">IS</span> <span class="hljs-keyword">NOT</span> <span class="hljs-keyword">NULL</span> <span class="hljs-keyword">AND</span> TABLE_SCHEMA <span class="hljs-keyword">NOT</span> <span class="hljs-keyword">IN</span> (<span class="hljs-string">'INFORMATION_SCHEMA'</span>, <span class="hljs-string">'mysql'</span>, <span class="hljs-string">'sys'</span>, <span class="hljs-string">'PERFORMANCE_SCHEMA'</span>, <span class="hljs-string">'METRICS_SCHEMA'</span>); </div><button class="MuiButtonBase-root MuiIconButton-root MuiIconButton-sizeSmall css-1rmx1rm" tabindex="0" type="button" aria-label="Toggle code wrap"><svg class="MuiSvgIcon-root MuiSvgIcon-fontSizeInherit css-1cw4hi4" focusable="false" aria-hidden="true" viewbox="0 0 24 24" data-testid="WrapTextIcon"><path d="M4 19h6v-2H4v2zM20 5H4v2h16V5zm-3 6H4v2h13.25c1.1 0 2 .9 2 2s-.9 2-2 2H15v-2l-3 3 3 3v-2h2c2.21 0 4-1.79 4-4s-1.79-4-4-4z"/></svg></button><button class="MuiButtonBase-root MuiIconButton-root MuiIconButton-sizeSmall css-fxo539" tabindex="0" type="button" aria-label="copy"><svg class="MuiSvgIcon-root MuiSvgIcon-fontSizeInherit css-1cw4hi4" focusable="false" aria-hidden="true" viewbox="0 0 24 24" data-testid="ContentCopyIcon"><path d="M16 1H4c-1.1 0-2 .9-2 2v14h2V3h12V1zm3 4H8c-1.1 0-2 .9-2 2v14c0 1.1.9 2 2 2h11c1.1 0 2-.9 2-2V7c0-1.1-.9-2-2-2zm0 16H8V7h11v14z"/></svg></button></code></pre><pre><code class="hljs language-"><div class="MuiBox-root css-1qhimia">+-------------------------------------+ | concat(TABLE_SCHEMA,'.',TABLE_NAME) | +-------------------------------------+ | test.t | +-------------------------------------+ 1 row in set (0.02 sec) </div><button class="MuiButtonBase-root MuiIconButton-root MuiIconButton-sizeSmall css-1rmx1rm" tabindex="0" type="button" aria-label="Toggle code wrap"><svg class="MuiSvgIcon-root MuiSvgIcon-fontSizeInherit css-1cw4hi4" focusable="false" aria-hidden="true" viewbox="0 0 24 24" data-testid="WrapTextIcon"><path d="M4 19h6v-2H4v2zM20 5H4v2h16V5zm-3 6H4v2h13.25c1.1 0 2 .9 2 2s-.9 2-2 2H15v-2l-3 3 3 3v-2h2c2.21 0 4-1.79 4-4s-1.79-4-4-4z"/></svg></button><button class="MuiButtonBase-root MuiIconButton-root MuiIconButton-sizeSmall css-fxo539" tabindex="0" type="button" aria-label="copy"><svg class="MuiSvgIcon-root MuiSvgIcon-fontSizeInherit css-1cw4hi4" focusable="false" aria-hidden="true" viewbox="0 0 24 24" data-testid="ContentCopyIcon"><path d="M16 1H4c-1.1 0-2 .9-2 2v14h2V3h12V1zm3 4H8c-1.1 0-2 .9-2 2v14c0 1.1.9 2 2 2h11c1.1 0 2-.9 2-2V7c0-1.1-.9-2-2-2zm0 16H8V7h11v14z"/></svg></button></code></pre></li><li><p>生成所有分区表的更新统计信息的语句：</p><pre><code class="hljs language-sql"><div class="MuiBox-root css-1qhimia"><span class="hljs-keyword">SELECT</span> <span class="hljs-keyword">DISTINCT</span> CONCAT(<span class="hljs-string">'ANALYZE TABLE '</span>,TABLE_SCHEMA,<span class="hljs-string">'.'</span>,TABLE_NAME,<span class="hljs-string">' ALL COLUMNS;'</span>) <span class="hljs-keyword">FROM</span> information_schema.PARTITIONS <span class="hljs-keyword">WHERE</span> TIDB_PARTITION_ID <span class="hljs-keyword">IS</span> <span class="hljs-keyword">NOT</span> <span class="hljs-keyword">NULL</span> <span class="hljs-keyword">AND</span> TABLE_SCHEMA <span class="hljs-keyword">NOT</span> <span class="hljs-keyword">IN</span> (<span class="hljs-string">'INFORMATION_SCHEMA'</span>,<span class="hljs-string">'mysql'</span>,<span class="hljs-string">'sys'</span>,<span class="hljs-string">'PERFORMANCE_SCHEMA'</span>,<span class="hljs-string">'METRICS_SCHEMA'</span>); </div><button class="MuiButtonBase-root MuiIconButton-root MuiIconButton-sizeSmall css-1rmx1rm" tabindex="0" type="button" aria-label="Toggle code wrap"><svg class="MuiSvgIcon-root MuiSvgIcon-fontSizeInherit css-1cw4hi4" focusable="false" aria-hidden="true" viewbox="0 0 24 24" data-testid="WrapTextIcon"><path d="M4 19h6v-2H4v2zM20 5H4v2h16V5zm-3 6H4v2h13.25c1.1 0 2 .9 2 2s-.9 2-2 2H15v-2l-3 3 3 3v-2h2c2.21 0 4-1.79 4-4s-1.79-4-4-4z"/></svg></button><button class="MuiButtonBase-root MuiIconButton-root MuiIconButton-sizeSmall css-fxo539" tabindex="0" type="button" aria-label="copy"><svg class="MuiSvgIcon-root MuiSvgIcon-fontSizeInherit css-1cw4hi4" focusable="false" aria-hidden="true" viewbox="0 0 24 24" data-testid="ContentCopyIcon"><path d="M16 1H4c-1.1 0-2 .9-2 2v14h2V3h12V1zm3 4H8c-1.1 0-2 .9-2 2v14c0 1.1.9 2 2 2h11c1.1 0 2-.9 2-2V7c0-1.1-.9-2-2-2zm0 16H8V7h11v14z"/></svg></button></code></pre><pre><code class="hljs language-"><div class="MuiBox-root css-1qhimia">+----------------------------------------------------------------------+ | concat('ANALYZE TABLE ',TABLE_SCHEMA,'.',TABLE_NAME,' ALL COLUMNS;') | +----------------------------------------------------------------------+ | ANALYZE TABLE test.t ALL COLUMNS; | +----------------------------------------------------------------------+ 1 row in set (0.01 sec) </div><button class="MuiButtonBase-root MuiIconButton-root MuiIconButton-sizeSmall css-1rmx1rm" tabindex="0" type="button" aria-label="Toggle code wrap"><svg class="MuiSvgIcon-root MuiSvgIcon-fontSizeInherit css-1cw4hi4" focusable="false" aria-hidden="true" viewbox="0 0 24 24" data-testid="WrapTextIcon"><path d="M4 19h6v-2H4v2zM20 5H4v2h16V5zm-3 6H4v2h13.25c1.1 0 2 .9 2 2s-.9 2-2 2H15v-2l-3 3 3 3v-2h2c2.21 0 4-1.79 4-4s-1.79-4-4-4z"/></svg></button><button class="MuiButtonBase-root MuiIconButton-root MuiIconButton-sizeSmall css-fxo539" tabindex="0" type="button" aria-label="copy"><svg class="MuiSvgIcon-root MuiSvgIcon-fontSizeInherit css-1cw4hi4" focusable="false" aria-hidden="true" viewbox="0 0 24 24" data-testid="ContentCopyIcon"><path d="M16 1H4c-1.1 0-2 .9-2 2v14h2V3h12V1zm3 4H8c-1.1 0-2 .9-2 2v14c0 1.1.9 2 2 2h11c1.1 0 2-.9 2-2V7c0-1.1-.9-2-2-2zm0 16H8V7h11v14z"/></svg></button></code></pre><p>可以按需将 <code>ALL COLUMNS</code> 改为实际需要的列。</p></li><li><p>将批量更新语句导出到文件：</p><pre><code class="hljs language-sh"><div class="MuiBox-root css-1qhimia">mysql --host xxxx --port xxxx -u root -p -e <span class="hljs-string">"SELECT DISTINCT CONCAT('ANALYZE TABLE ',TABLE_SCHEMA,'.',TABLE_NAME,' ALL COLUMNS;') \ FROM information_schema.PARTITIONS \ WHERE TIDB_PARTITION_ID IS NOT NULL \