运算符 · k8s原理与实践

[TOC] # 算术运算符以下为所有算术运算符列表： <table data-tag="table" id="table-y8m-guy-1m8" class="table"><colgroup data-tag="col" id="col-n7e-75m-etx" colwidth="1*" colnum="1" colname="col1" style="width:33.33333333333333%" class="col"></colgroup><colgroup data-tag="col" id="col-orp-uf4-72j" colwidth="1*" colnum="2" colname="col2" style="width:33.33333333333333%" class="col"></colgroup><colgroup data-tag="col" id="col-xj4-nqa-r1v" colwidth="1*" colnum="3" colname="col3" style="width:33.33333333333333%" class="col"></colgroup><thead id="thead-8so-3ko-7bu" class="thead"><tr id="tr-11b-tli-gtl"><th id="td-i5f-jtd-qyz">运算符</th><th id="td-abr-tx3-aou">操作数</th><th id="td-r9c-o74-eps">含义</th></tr></thead><tbody data-tag="tbody" id="tbody-wbo-qyj-0s7" class="tbody"><tr data-tag="tr" id="tr-69l-fsa-dk6" class="tr"><td data-tag="td" id="td-it1-b9d-1jz" class="td"><code data-tag="code" class="code">+</code></td><td data-tag="td" id="td-45a-rf5-8ak" class="td">一元/二元</td><td data-tag="td" id="td-b8z-ptf-cji" class="td">一元表示正数，二元表示加法。</td></tr><tr data-tag="tr" id="tr-puc-oaj-i3j" class="tr"><td data-tag="td" id="td-k41-dnu-sa8" class="td"><code data-tag="code" class="code">-</code></td><td data-tag="td" id="td-6vw-8fw-0oh" class="td">一元/二元</td><td data-tag="td" id="td-pm6-qi4-k0q" class="td">一元表示负数，二元表示减法。</td></tr><tr data-tag="tr" id="tr-vp7-1pi-egc" class="tr"><td data-tag="td" id="td-8em-6vk-k8w" class="td"><code data-tag="code" class="code">*</code></td><td data-tag="td" id="td-aa9-e0b-omr" class="td">二元</td><td data-tag="td" id="td-bm9-7l8-ss0" class="td">乘法。</td></tr><tr data-tag="tr" id="tr-swi-8yp-eec" class="tr"><td data-tag="td" id="td-xhg-yh7-3y7" class="td"><code data-tag="code" class="code">/</code></td><td data-tag="td" id="td-j7g-xpm-29o" class="td">二元</td><td data-tag="td" id="td-s0c-00m-kd4" class="td">普通除法。</td></tr><tr data-tag="tr" id="tr-rv3-jbl-qh4" class="tr"><td data-tag="td" id="td-514-1ww-fqy" class="td"><code data-tag="code" class="code">DIV</code></td><td data-tag="td" id="td-vht-ht2-lfu" class="td">二元</td><td data-tag="td" id="td-d4m-d06-qsp" class="td">整数除法，返回商数。</td></tr><tr data-tag="tr" id="tr-pys-uzd-ed7" class="tr"><td data-tag="td" id="td-lt6-7ud-xuv" class="td"><code data-tag="code" class="code">MOD</code>或<code data-tag="code" class="code">%</code></td><td data-tag="td" id="td-lla-g3i-nfm" class="td">二元</td><td data-tag="td" id="td-2tv-1p6-ji6" class="td">整数除法，返回余数。</td></tr></tbody></table> 整数除法遵循如下原则： * 商数不论正负，统一向0取整。 * 余数正负与被除数相同。例如： ~~~ OceanBase (root@oceanbase)> SELECT (-7) DIV (3.6), (-7) MOD (3.6); +----------------+----------------+ | (-7) DIV (3.6) | (-7) MOD (3.6) | +----------------+----------------+ | -1 | -3.4 | +----------------+----------------+ 1 row in set (0.01 sec) OceanBase (root@oceanbase)> SELECT (-7) DIV (-3.4), (-7) % (-3.4); +-----------------+---------------+ | (-7) DIV (-3.4) | (-7) % (-3.4) | +-----------------+---------------+ | 2 | -0.2 | +-----------------+---------------+ 1 row in set (0.02 sec) ~~~ # 位运算符位运算使用`BIGINT UNSIGNED`计算，不需考虑符号位。以下为所有位运算符列表： <table data-tag="table" id="table-y02-7n1-bm2" class="table"><colgroup data-tag="col" id="col-pbv-1z5-p8o" colwidth="1*" colnum="1" colname="col1" style="width:33.33333333333333%" class="col"></colgroup><colgroup data-tag="col" id="col-bwk-yb5-oji" colwidth="1*" colnum="2" colname="col2" style="width:33.33333333333333%" class="col"></colgroup><colgroup data-tag="col" id="col-m2l-zv6-h5k" colwidth="1*" colnum="3" colname="col3" style="width:33.33333333333333%" class="col"></colgroup><thead id="thead-sbs-cyo-0pv" class="thead"><tr id="tr-s9j-pue-7uk"><th id="td-w41-0pa-pw4">运算符</th><th id="td-pt5-hqi-vbn">操作数</th><th id="td-10o-hb1-3af">含义</th></tr></thead><tbody data-tag="tbody" id="tbody-4fu-fjq-pwi" class="tbody"><tr data-tag="tr" id="tr-5dn-5nr-zna" class="tr"><td data-tag="td" id="td-ok8-wv0-eg8" class="td"><code data-tag="code" class="code">&amp;</code></td><td data-tag="td" id="td-446-59n-jp0" class="td">二元</td><td data-tag="td" id="td-jdg-2f4-nsc" class="td">按位与。</td></tr><tr data-tag="tr" id="tr-92i-cva-oeq" class="tr"><td data-tag="td" id="td-anc-e81-kj5" class="td"><code data-tag="code" class="code">|</code></td><td data-tag="td" id="td-lo4-k5e-tqc" class="td">二元</td><td data-tag="td" id="td-f68-x16-2ty" class="td">按位或。</td></tr><tr data-tag="tr" id="tr-7e0-40n-sal" class="tr"><td data-tag="td" id="td-xau-dqa-zi4" class="td"><code data-tag="code" class="code">~</code></td><td data-tag="td" id="td-8cy-rdo-tbp" class="td">一元</td><td data-tag="td" id="td-7lq-wsn-ovi" class="td">按位取反。</td></tr><tr data-tag="tr" id="tr-3vr-dhi-m8h" class="tr"><td data-tag="td" id="td-npq-eki-rpz" class="td"><code data-tag="code" class="code">^</code></td><td data-tag="td" id="td-mw1-qwi-t1s" class="td">二元</td><td data-tag="td" id="td-cto-muj-v40" class="td">按位异或。</td></tr><tr data-tag="tr" id="tr-7ca-9xw-evo" class="tr"><td data-tag="td" id="td-y0n-qon-wjv" class="td"><code data-tag="code" class="code">&lt;&lt;</code></td><td data-tag="td" id="td-3uz-vqe-umq" class="td">二元</td><td data-tag="td" id="td-th4-gw7-t34" class="td">逻辑左移。</td></tr><tr data-tag="tr" id="tr-q0a-3bp-fx0" class="tr"><td data-tag="td" id="td-rth-wki-kja" class="td"><code data-tag="code" class="code">&gt;&gt;</code></td><td data-tag="td" id="td-yfv-59d-sv2" class="td">二元</td><td data-tag="td" id="td-ymq-pqy-647" class="td">逻辑右移。</td></tr></tbody></table> # 比较运算符以下为所有比较运算符列表： <table data-tag="table" id="table-y2x-mir-8do" class="table"><colgroup data-tag="col" id="col-vdb-127-gh0" colwidth="1*" colnum="1" colname="col1" style="width:25%" class="col"></colgroup><colgroup data-tag="col" id="col-jr6-kpn-m29" colwidth="1*" colnum="2" colname="col2" style="width:25%" class="col"></colgroup><colgroup data-tag="col" id="col-6zt-k9l-nhw" colwidth="1*" colnum="3" colname="col3" style="width:25%" class="col"></colgroup><colgroup data-tag="col" id="col-cib-0sm-of8" colwidth="1*" colnum="4" colname="col4" style="width:25%" class="col"></colgroup><thead id="thead-5mt-7ui-cx1" class="thead"><tr id="tr-2nr-jkd-uzt"><th id="td-x8z-yt4-f60">运算符</th><th id="td-3t4-m68-k8f">操作数</th><th id="td-338-8qs-vun">含义</th><th id="td-urt-p25-xn1">NULL参与运算</th></tr></thead><tbody data-tag="tbody" id="tbody-xwa-4uc-gms" class="tbody"><tr data-tag="tr" id="tr-w5j-lv6-nka" class="tr"><td data-tag="td" id="td-fd8-bul-kq2" class="td"><code data-tag="code" class="code">=</code></td><td data-tag="td" id="td-2kt-vi8-8xn" class="td">二元</td><td data-tag="td" id="td-8bm-c76-6zn" class="td">等于。</td><td data-tag="td" id="td-eq1-ue5-tq9" class="td">结果为NULL。</td></tr><tr data-tag="tr" id="tr-v3w-k66-yo9" class="tr"><td data-tag="td" id="td-6d1-rda-wqb" class="td"><code data-tag="code" class="code">&lt;&gt;</code>/<code data-tag="code" class="code">!=</code></td><td data-tag="td" id="td-d3n-wix-v3v" class="td">二元</td><td data-tag="td" id="td-4dk-bhk-5i8" class="td">不等于。</td><td data-tag="td" id="td-cfq-f1m-o19" class="td">结果为NULL。</td></tr><tr data-tag="tr" id="tr-g4z-j9l-f5i" class="tr"><td data-tag="td" id="td-stx-3rv-3mj" class="td"><code data-tag="code" class="code">&gt;</code></td><td data-tag="td" id="td-hrz-uy4-6vs" class="td">二元</td><td data-tag="td" id="td-3xn-ict-7xm" class="td">大于。</td><td data-tag="td" id="td-22m-huw-15e" class="td">结果为NULL。</td></tr><tr data-tag="tr" id="tr-9si-cmi-y77" class="tr"><td data-tag="td" id="td-xj6-y4g-nxq" class="td"><code data-tag="code" class="code">&gt;=</code></td><td data-tag="td" id="td-n8c-xte-lbs" class="td">二元</td><td data-tag="td" id="td-ae7-zj9-vcg" class="td">大于等于。</td><td data-tag="td" id="td-u6i-zym-wqc" class="td">结果为NULL。</td></tr><tr data-tag="tr" id="tr-sn0-rbs-8v5" class="tr"><td data-tag="td" id="td-13m-iqs-7rz" class="td"><code data-tag="code" class="code">&lt;</code></td><td data-tag="td" id="td-xfh-985-le2" class="td">二元</td><td data-tag="td" id="td-wb7-wpp-3rj" class="td">小于。</td><td data-tag="td" id="td-1o0-sng-hsn" class="td">结果为NULL。</td></tr><tr data-tag="tr" id="tr-kd8-xul-tlb" class="tr"><td data-tag="td" id="td-u6a-g4d-jt3" class="td"><code data-tag="code" class="code">&lt;=</code></td><td data-tag="td" id="td-ts3-abl-1w5" class="td">二元</td><td data-tag="td" id="td-632-53w-lf4" class="td">小于等于。</td><td data-tag="td" id="td-3bo-07k-0od" class="td">结果为NULL。</td></tr><tr data-tag="tr" id="tr-xr8-i2u-28w" class="tr"><td data-tag="td" id="td-xql-1ks-nyr" class="td"><code data-tag="code" class="code">[NOT] IN</code></td><td data-tag="td" id="td-u9d-aoy-w6n" class="td">二元</td><td data-tag="td" id="td-lrs-a23-lyl" class="td">是否在集合中。</td><td data-tag="td" id="td-jc4-uyc-ewn" class="td">详见说明。</td></tr><tr data-tag="tr" id="tr-r0d-pyi-c8j" class="tr"><td data-tag="td" id="td-nhk-vkp-8vo" class="td"><code data-tag="code" class="code">[NOT] BETWEEN AND</code></td><td data-tag="td" id="td-yd8-xlz-spi" class="td">三元</td><td data-tag="td" id="td-q4e-zr5-umh" class="td">是否在区间内。</td><td data-tag="td" id="td-2rr-ha1-biz" class="td">详见说明。</td></tr><tr data-tag="tr" id="tr-rh4-716-u22" class="tr"><td data-tag="td" id="td-sot-mnu-oj1" class="td"><code data-tag="code" class="code">IS [NOT] TRUE</code></td><td data-tag="td" id="td-7g0-6xp-5ew" class="td">一元</td><td data-tag="td" id="td-e3z-u86-or4" class="td">是否等于TRUE。</td><td data-tag="td" id="td-c16-c16-o1m" class="td">结果为TRUE或FALSE。</td></tr><tr data-tag="tr" id="tr-p6h-v65-qgw" class="tr"><td data-tag="td" id="td-1o1-78a-c75" class="td"><code data-tag="code" class="code">IS [NOT] FALSE</code></td><td data-tag="td" id="td-o5y-lav-bnu" class="td">一元</td><td data-tag="td" id="td-irq-5lb-nhp" class="td">是否等于FALSE。</td><td data-tag="td" id="td-eob-vaj-t1m" class="td">结果为TRUE或FALSE。</td></tr><tr data-tag="tr" id="tr-7e7-g2r-hlt" class="tr"><td data-tag="td" id="td-3qt-dq6-low" class="td"><code data-tag="code" class="code">IS [NOT] NULL</code></td><td data-tag="td" id="td-mxv-5ue-h5q" class="td">一元</td><td data-tag="td" id="td-s75-gu2-q1n" class="td">是否等于NULL。</td><td data-tag="td" id="td-y0w-r3m-gbe" class="td">结果为TRUE或FALSE。</td></tr><tr data-tag="tr" id="tr-ng3-zbv-frg" class="tr"><td data-tag="td" id="td-kgf-bpt-f16" class="td"><code data-tag="code" class="code">&lt;=&gt;</code></td><td data-tag="td" id="td-ll2-9hk-yh2" class="td">二元</td><td data-tag="td" id="td-mk9-pj7-pp8" class="td">安全等于。</td><td data-tag="td" id="td-zs0-no4-rch" class="td">结果为TRUE或FALSE。</td></tr></tbody></table> # 逻辑运算符以下为所有逻辑运算符列表： <table data-tag="table" id="table-rls-0v9-rxr" class="table"><colgroup data-tag="col" id="col-k3v-l5n-zw1" colwidth="1*" colnum="1" colname="col1" style="width:33.33333333333333%" class="col"></colgroup><colgroup data-tag="col" id="col-257-msn-3oc" colwidth="1*" colnum="2" colname="col2" style="width:33.33333333333333%" class="col"></colgroup><colgroup data-tag="col" id="col-lss-3p9-6un" colwidth="1*" colnum="3" colname="col3" style="width:33.33333333333333%" class="col"></colgroup><thead id="thead-ivc-g0r-1o2" class="thead"><tr id="tr-evx-106-rcp"><th id="td-sp2-n4r-7ac">运算符</th><th id="td-xyh-x6i-ph4">操作数</th><th id="td-478-o2r-iqx">含义</th></tr></thead><tbody data-tag="tbody" id="tbody-qf6-6kp-mzc" class="tbody"><tr data-tag="tr" id="tr-mt9-xvh-ulq" class="tr"><td data-tag="td" id="td-4da-6zc-fwd" class="td"><code data-tag="code" class="code">AND</code>/<code data-tag="code" class="code">&amp;&amp;</code></td><td data-tag="td" id="td-d99-v1g-qeh" class="td">二元</td><td data-tag="td" id="td-a11-m6t-lzs" class="td">逻辑与</td></tr><tr data-tag="tr" id="tr-uyp-dtx-cei" class="tr"><td data-tag="td" id="td-o4u-bpr-ph2" class="td"><code data-tag="code" class="code">OR</code>/<code data-tag="code" class="code">||</code></td><td data-tag="td" id="td-qjf-vma-brq" class="td">二元</td><td data-tag="td" id="td-f02-int-5q5" class="td">逻辑或</td></tr><tr data-tag="tr" id="tr-0gb-e0y-s47" class="tr"><td data-tag="td" id="td-ofe-k5q-i1h" class="td"><code data-tag="code" class="code">NOT</code>/<code data-tag="code" class="code">!</code></td><td data-tag="td" id="td-0xt-9oz-zhg" class="td">一元</td><td data-tag="td" id="td-bbp-0yu-487" class="td">逻辑非</td></tr></tbody></table> # 日期时间运算符以下为所有日期时间运算符列表： <table data-tag="table" id="table-kma-swc-4n0" class="table"><colgroup data-tag="col" id="col-oza-qgz-ff8" colwidth="1*" colnum="1" colname="col1" style="width:33.33333333333333%" class="col"></colgroup><colgroup data-tag="col" id="col-56h-hue-7s9" colwidth="1*" colnum="2" colname="col2" style="width:33.33333333333333%" class="col"></colgroup><colgroup data-tag="col" id="col-jid-r07-d7n" colwidth="1*" colnum="3" colname="col3" style="width:33.33333333333333%" class="col"></colgroup><thead id="thead-8ox-ws1-vk4" class="thead"><tr id="tr-s1x-k20-2kf"><th id="td-yjk-dqu-jj7">运算符</th><th id="td-bzx-dvc-ml4">操作数</th><th id="td-w53-7qt-ggl">含义</th></tr></thead><tbody data-tag="tbody" id="tbody-poz-8bg-x2y" class="tbody"><tr data-tag="tr" id="tr-o7s-4sj-u2f" class="tr"><td data-tag="td" id="td-5oa-fh8-hn6" class="td"><code data-tag="code" class="code">+</code></td><td data-tag="td" id="td-rjx-9cd-zb9" class="td">二元</td><td data-tag="td" id="td-toy-r9r-9in" class="td">同<code data-tag="code" class="code">DATE_ADD</code>函数</td></tr><tr data-tag="tr" id="tr-xwp-a4o-mwp" class="tr"><td data-tag="td" id="td-9kr-k5d-0v3" class="td"><code data-tag="code" class="code">-</code></td><td data-tag="td" id="td-7fn-6nf-qef" class="td">二元</td><td data-tag="td" id="td-c8q-xx6-xw2" class="td">同<code data-tag="code" class="code">DATE_SUB</code>函数</td></tr></tbody></table> 例如： ~~~ OceanBase (root@oceanbase)> SELECT '2008-12-31 23:59:59' + INTERVAL 1 SECOND; +-------------------------------------------+ | '2008-12-31 23:59:59' + INTERVAL 1 SECOND | +-------------------------------------------+ | 2009-01-01 00:00:00 | +-------------------------------------------+ 1 row in set (0.01 sec) ~~~ # 字符连接运算符以下为所有字符连接运算符列表： <table data-tag="table" id="table-7tg-bcv-ahk" class="table"><colgroup data-tag="col" id="col-c4v-hns-8op" colwidth="1*" colnum="1" colname="col1" style="width:33.33333333333333%" class="col"></colgroup><colgroup data-tag="col" id="col-tf7-duu-mon" colwidth="1*" colnum="2" colname="col2" style="width:33.33333333333333%" class="col"></colgroup><colgroup data-tag="col" id="col-mcw-zcc-llm" colwidth="1*" colnum="3" colname="col3" style="width:33.33333333333333%" class="col"></colgroup><thead id="thead-5sj-njl-1ac" class="thead"><tr id="tr-v5g-jl9-s0v"><th id="td-fgh-4ma-zm3">运算符</th><th id="td-e4e-pe8-ydg">操作数</th><th id="td-uuo-awd-c9w">含义</th></tr></thead><tbody data-tag="tbody" id="tbody-ewt-lif-gkh" class="tbody"><tr data-tag="tr" id="tr-rt5-u37-6yx" class="tr"><td data-tag="td" id="td-dnn-20o-mzl" class="td"><code data-tag="code" class="code">||</code></td><td data-tag="td" id="td-t1j-ben-ftq" class="td">二元</td><td data-tag="td" id="td-f1u-auq-n4x" class="td">字符串连接</td></tr></tbody></table> 如前节所述，`||`也可作为逻辑或运算符，两个不同含义是通过SQL MODE控制的： * SQL MODE包含`PIPES_AS_CONCAT`时，`||`为字符连接运算符。 * SQL MODE不包含`PIPES_AS_CONCAT`时，`||`为逻辑与运算符 # 层次查询运算符以下为所有层次查询运算符列表： <table data-tag="table" id="table-tt8-q9d-56l" class="table"><colgroup data-tag="col" id="col-s4h-624-4c2" colwidth="1*" colnum="2" colname="col2" style="width:33.33333333333333%" class="col"></colgroup><colgroup data-tag="col" id="col-t96-nor-36k" colwidth="1*" colnum="3" colname="col3" style="width:33.33333333333333%" class="col"></colgroup><thead id="thead-z5b-77r-4sp" class="thead"><tr id="tr-59s-siq-wrb"><th id="td-rcz-3as-23s">运算符</th><th id="td-2ln-11j-c60">操作数</th><th id="td-ybz-fqu-ykj">含义</th></tr></thead><tbody data-tag="tbody" id="tbody-ebc-3ns-m63" class="tbody"><tr data-tag="tr" id="tr-w57-rs9-8sa" class="tr"><td data-tag="td" id="td-vl3-qt3-72b" class="td"><code data-tag="code" class="code">PRIOR</code></td><td data-tag="td" id="td-j7f-3ci-ifk" class="td">一元</td><td data-tag="td" id="td-q4a-jkn-nqr" class="td">用于指明column来自parent row</td></tr><tr data-tag="tr" id="tr-vvn-z1u-66y" class="tr"><td data-tag="td" id="td-alq-6ot-cg8" class="td"><code data-tag="code" class="code">CONNECT_BY_ROOT</code></td><td data-tag="td" id="td-ela-a4f-6ms" class="td">一元</td><td data-tag="td" id="td-wny-h4a-9k2" class="td">用于指明顶层祖先</td></tr></tbody></table> # 排序规则运算符以下为所有排序规则运算符列表： <table data-tag="table" id="table-ej7-j1x-tk2" class="table"><colgroup data-tag="col" id="col-632-pdg-f7v" colwidth="1*" colnum="1" colname="col1" style="width:33.33333333333333%" class="col"></colgroup><colgroup data-tag="col" id="col-ul9-2hm-w46" colwidth="1*" colnum="2" colname="col2" style="width:33.33333333333333%" class="col"></colgroup><colgroup data-tag="col" id="col-x3l-xlh-g0i" colwidth="1*" colnum="3" colname="col3" style="width:33.33333333333333%" class="col"></colgroup><thead id="thead-j9k-5kx-52y" class="thead"><tr id="tr-vh4-jqc-07i"><th id="td-wjb-0q3-lgf">运算符</th><th id="td-2kh-t9k-t6e">操作数</th><th id="td-dlr-g0w-wlz">含义</th></tr></thead><tbody data-tag="tbody" id="tbody-hax-ld9-5sc" class="tbody"><tr data-tag="tr" id="tr-5ok-pkc-p9j" class="tr"><td data-tag="td" id="td-yy5-oai-a1e" class="td"><code data-tag="code" class="code">COLLATE</code></td><td data-tag="td" id="td-lic-6jr-6tg" class="td">一元（后缀）</td><td data-tag="td" id="td-oz4-onk-bxp" class="td">排序规则</td></tr></tbody></table> 例如： ~~~ SELECT last_name FROM employees ORDER BY last_name COLLATE UTF8MB4_GENERAL_CI; ~~~