# 關于 SQL 數據類型 當您創建表的時候，必須指定表記錄行的每一列的數據類型，數據類型定義了該列存儲數據的合法格式。比如說一個 DATE 類型的列，能存儲值“2020-02-20”，但是不能存儲值為 2 的數字或者字符串“hello”。 有關 SQL 數據類型的詳細描述，請參考《SQL參考（MySQL模式）》，這里介紹一些常用的數據類型。 <table data-tag="table" id="table-321-ldo-xg6" class="table"><colgroup width="192" span="1" data-tag="col" id="col-dgc-ues-i5q" colwidth="1*" colnum="1" colname="col1" style="width:33.33333333333333%" class="col"></colgroup><colgroup width="153" span="1" data-tag="col" id="col-ito-erf-nz0" colwidth="1*" colnum="2" colname="col2" style="width:33.33333333333333%" class="col"></colgroup><colgroup width="308" span="1" data-tag="col" id="col-ib1-qp4-1ex" colwidth="1*" colnum="3" colname="col3" style="width:33.33333333333333%" class="col"></colgroup><thead id="thead-o5z-13e-wqz" class="thead"><tr id="tr-pny-73r-gs3"><th id="td-8xu-iy1-l14"><p id="p-7wm-2i4-98g"><b>分類</b></p></th><th id="td-90e-cu1-gx1"><p id="p-weq-m1p-fgm"><b>類型</b></p></th><th id="td-zzw-j98-azp"><p id="p-mq4-xca-ogk"><b>備注</b></p></th></tr></thead><tbody data-tag="tbody" id="tbody-mjd-60h-spx" class="tbody"><tr data-tag="tr" id="tr-gxm-soz-isr" class="tr"><td data-tag="td" id="td-kzl-8u8-680" rowspan="4" class="td"><p data-tag="p" id="p-o9n-51q-vcu" class="p">數值類型-整形</p></td><td data-tag="td" id="td-tse-upk-s9z" class="td"><p data-tag="p" id="p-tze-i93-2s8" class="p">bigint</p></td><td data-tag="td" id="td-7ys-xri-8sk" class="td"><p data-tag="p" id="p-fxz-o8n-tpk" class="p">有符號：[-2^63, 2^63 - 1]</p><p data-tag="p" id="p-7cw-5cq-5j9" class="p">無符號：[0, 2^64 - 1]</p></td></tr><tr data-tag="tr" id="tr-lfl-8qp-m3n" class="tr"><td data-tag="td" id="td-sp1-9en-2h9" class="td"><p data-tag="p" id="p-g54-zu7-omf" class="p">int</p><p data-tag="p" id="p-x52-878-5bf" class="p">integer</p></td><td data-tag="td" id="td-fip-gfm-wpa" class="td"><p data-tag="p" id="p-ejz-xj7-ehp" class="p">有符號：[-2^31, 2^31-1]</p><p data-tag="p" id="p-lbv-v5i-ids" class="p">無符號：[0, 2^32-1]</p></td></tr><tr data-tag="tr" id="tr-swy-9m7-d0i" class="tr"><td data-tag="td" id="td-4um-1rk-szm" class="td"><p data-tag="p" id="p-bwg-shk-e1d" class="p">smallint</p></td><td data-tag="td" id="td-mpt-hun-x2x" class="td"><p data-tag="p" id="p-jfk-7k0-kz6" class="p">有符號：[-2^15, 2^15-1]</p><p data-tag="p" id="p-8x2-dm3-ghy" class="p">無符號：[0, 2^16-1]</p></td></tr><tr data-tag="tr" id="tr-v9h-e7u-46o" class="tr"><td data-tag="td" id="td-o5i-os6-eft" class="td"><p data-tag="p" id="p-7rf-e0j-r1m" class="p">bool</p><p data-tag="p" id="p-5dv-vrc-a68" class="p">boolean</p><p data-tag="p" id="p-gp4-xcu-y90" class="p">tinyint</p></td><td data-tag="td" id="td-64g-y2d-g1e" class="td"><p data-tag="p" id="p-xlk-3w3-wvb" class="p">有符號：[-2^7, 2^7-1]</p><p data-tag="p" id="p-1t8-vao-l9t" class="p">無符號：[0, 2^8-1]</p></td></tr><tr data-tag="tr" id="tr-oe6-i03-qgn" class="tr"><td data-tag="td" id="td-qs3-8te-nj4" class="td"><p data-tag="p" id="p-v7z-6z5-cuo" class="p">數值類型-定點</p></td><td data-tag="td" id="td-ajz-qgc-dpq" class="td"><p data-tag="p" id="p-3py-ard-wnz" class="p">decimal(p, s)</p></td><td data-tag="td" id="td-rtn-0g1-999" class="td"><p data-tag="p" id="p-i0w-on4-xny" class="p">decimal 等同于 numeric</p></td></tr><tr data-tag="tr" id="tr-g7y-h41-4s7" class="tr"><td data-tag="td" id="td-d2d-lx2-nma" rowspan="2" class="td"><p data-tag="p" id="p-sam-v3h-g79" class="p">數值類型-浮點</p></td><td data-tag="td" id="td-d8j-80g-l2b" class="td"><p data-tag="p" id="p-z3l-j6c-koj" class="p">float</p></td><td data-tag="td" id="td-vg4-e73-ryo" class="td"><p data-tag="p" id="p-5dp-r3u-p9g" class="p">有符號：[-2^128, 2^128]</p><p data-tag="p" id="p-kao-bq2-o82" class="p">無符號：[-2^1024, 2^1024]</p><p data-tag="p" id="p-dju-v9s-v3n" class="p">精度7位</p></td></tr><tr data-tag="tr" id="tr-p5f-u0k-9ux" class="tr"><td data-tag="td" id="td-9yi-g13-cmu" class="td"><p data-tag="p" id="p-zqg-2qv-3ur" class="p">double</p></td><td data-tag="td" id="td-goc-st6-8id" class="td"><p data-tag="p" id="p-p3j-wxm-8ed" class="p">有符號：[-2^1024, 2^1024]</p><p data-tag="p" id="p-2mq-cj4-c7d" class="p">無符號：[0, 2^1024]</p><p data-tag="p" id="p-k1r-054-4gl" class="p">精度15位</p></td></tr><tr data-tag="tr" id="tr-cln-kwb-ipw" class="tr"><td data-tag="td" id="td-o5y-gpa-4cz" class="td"><p data-tag="p" id="p-tsf-j5e-k3h" class="p">數值類型- 整形/定點/浮點</p></td><td data-tag="td" id="td-clx-lty-a3s" class="td"><p data-tag="p" id="p-7l8-l18-vj0" class="p">number</p><p data-tag="p" id="p-6bu-q48-y8c" class="p">number(p)</p><p data-tag="p" id="p-ag6-c73-pcs" class="p">number(p, s)</p></td><td data-tag="td" id="td-523-92l-qv6" class="td"><p data-tag="p" id="p-r1n-8wj-udh" class="p">p(precision) 為精度，s(scale) 表示小數點右邊的數字個數，精度最大值為 38，scale 的取值范圍為 -84 到 127。</p><ul lake-indent="0" data-tag="ul" id="ul-mec-dbf-ddr" class="ul"><li data-tag="li" id="li-25p-527-um9" class="li"><p id="p-gpv-6qe-vxh">p 和 s 都有表示定點數。</p></li><li data-tag="li" id="li-1a0-f1v-q0i" class="li"><p id="p-ggn-iao-olu">s 為 0 表示整形。</p></li><li data-tag="li" id="li-2q0-ji5-rwa" class="li"><p id="p-je8-zl8-r8a">p 和 s 都不指定，表示浮點數，最大精度 38。</p></li></ul></td></tr><tr data-tag="tr" id="tr-1wa-vj5-mm7" class="tr"><td data-tag="td" id="td-3tp-jr6-kl2" rowspan="4" class="td"><p data-tag="p" id="p-luh-esq-qq4" class="p">字符類型-變長</p></td><td data-tag="td" id="td-xu1-p0j-pr4" class="td"><p data-tag="p" id="p-ote-woc-ofh" class="p">varchar(N)</p></td><td data-tag="td" id="td-d5k-8zo-5pm" class="td"><p data-tag="p" id="p-xe6-bmb-8r9" class="p">最長 256K，字符集 UTF8MB4</p></td></tr><tr data-tag="tr" id="tr-0ge-hix-nfl" class="tr"><td data-tag="td" id="td-o0x-9jk-5ws" class="td"><p data-tag="p" id="p-fpt-c6i-x2m" class="p">varbinary</p></td><td data-tag="td" id="td-vld-8w6-hfb" class="td"><p data-tag="p" id="p-1e8-shw-nt4" class="p">最初 256K，字符集 BINARY</p></td></tr><tr data-tag="tr" id="tr-raf-k4r-1ep" class="tr"><td data-tag="td" id="td-h4t-1s1-q39" class="td"><p data-tag="p" id="p-l49-xqv-dlz" class="p">enum</p></td><td data-tag="td" id="td-euf-zij-ndu" class="td"><p data-tag="p" id="p-yjp-u2u-wwl" class="p">最多 65535 個元素，每個元素最長 255 個字符，字符集 UTF8MB4</p></td></tr><tr data-tag="tr" id="tr-wsc-fvg-kx7" class="tr"><td data-tag="td" id="td-v2p-j78-dac" class="td"><p data-tag="p" id="p-as8-r2d-g7b" class="p">set</p></td><td data-tag="td" id="td-jwx-dhx-cgj" class="td"><p data-tag="p" id="p-2xv-372-lc3" class="p">最多 64 個元素，每個元素最長255 個字符，字符集 UTF8MB4</p></td></tr><tr data-tag="tr" id="tr-1o5-u0l-li6" class="tr"><td data-tag="td" id="td-82d-0xs-tpg" rowspan="2" class="td"><p data-tag="p" id="p-5lz-azp-hh3" class="p">字符類型-定長</p></td><td data-tag="td" id="td-tjx-pl9-t8j" class="td"><p data-tag="p" id="p-3lk-xzg-h8a" class="p">char(N)</p></td><td data-tag="td" id="td-n65-n8o-ksx" class="td"><p data-tag="p" id="p-3ac-fen-q7y" class="p">最大 256，字符集 UTF8MB4</p></td></tr><tr data-tag="tr" id="tr-tfa-pmn-71o" class="tr"><td data-tag="td" id="td-6k0-0gn-sqy" class="td"><p data-tag="p" id="p-tcd-ip9-j00" class="p">binary</p></td><td data-tag="td" id="td-exl-qwf-cix" class="td"><p data-tag="p" id="p-fng-rg2-qzk" class="p">最大 256，字符集 BINARY</p></td></tr><tr data-tag="tr" id="tr-boz-a8x-kjv" class="tr"><td data-tag="td" id="td-m3q-7sw-zpu" rowspan="5" class="td"><p data-tag="p" id="p-4l1-ij4-b9u" class="p">時間類型</p></td><td data-tag="td" id="td-u97-pxp-96x" class="td"><p data-tag="p" id="p-gwa-6nj-phf" class="p">date</p></td><td data-tag="td" id="td-gin-hsp-278" class="td"><p data-tag="p" id="p-qxc-05g-a3r" class="p">YYYY-MM-DD，只包含日期</p></td></tr><tr data-tag="tr" id="tr-2dn-urc-jt8" class="tr"><td data-tag="td" id="td-5v8-wgk-50n" class="td"><p data-tag="p" id="p-eko-mxd-i1x" class="p">time</p></td><td data-tag="td" id="td-91p-k7d-zmk" class="td"><p data-tag="p" id="p-qam-nuq-8nn" class="p">HH:MM:SS[.fraction]，只包含時間。</p></td></tr><tr data-tag="tr" id="tr-qg9-y93-s8t" class="tr"><td data-tag="td" id="td-xz2-1oy-cja" class="td"><p data-tag="p" id="p-l0p-t6f-ox1" class="p">datetime</p></td><td data-tag="td" id="td-msa-mgk-anz" class="td"><p data-tag="p" id="p-x4y-pm1-5g3" class="p">YYYY-MM-DD HH:MM:SS[.fraction]，包含日期時間(不考慮時區)。</p></td></tr><tr data-tag="tr" id="tr-k33-3ic-01j" class="tr"><td data-tag="td" id="td-1zc-yud-5c0" class="td"><p data-tag="p" id="p-tpw-6sd-z0a" class="p">Timestamp</p></td><td data-tag="td" id="td-qby-wqf-9nj" class="td"><p data-tag="p" id="p-q4m-j1p-7b0" class="p">日期時間(考慮時區)。</p></td></tr><tr data-tag="tr" id="tr-zr6-dxv-shd" class="tr"><td data-tag="td" id="td-vza-79c-wj7" class="td"><p data-tag="p" id="p-4v9-mjh-p4a" class="p">year</p></td><td data-tag="td" id="td-d0a-bic-pib" class="td"><p data-tag="p" id="p-ssn-qac-cmb" class="p">YYYY,[1901, 2155]</p></td></tr><tr data-tag="tr" id="tr-uml-euj-mx7" class="tr"><td data-tag="td" id="td-x4h-eh3-giw" rowspan="2" class="td"><p data-tag="p" id="p-gw3-4kc-tqz" class="p">大對象</p></td><td data-tag="td" id="td-ll4-mq2-acq" class="td"><p data-tag="p" id="p-3tl-79v-xjl" class="p">Text / blob</p></td><td data-tag="td" id="td-afl-o5y-0gw" class="td"><p data-tag="p" id="p-lgi-75u-t6h" class="p">最大 64K</p></td></tr><tr data-tag="tr" id="tr-8hs-ny5-2eo" class="tr"><td data-tag="td" id="td-gsg-yp8-2b6" class="td"><p data-tag="p" id="p-ngq-1f6-l1i" class="p">Longtext /longblob</p></td><td data-tag="td" id="td-mta-35u-qid" class="td"><p data-tag="p" id="p-nc2-16d-lvp" class="p">最大 48M</p></td></tr></tbody></table>