{"id":173,"date":"2019-07-09T09:47:22","date_gmt":"2019-07-09T01:47:22","guid":{"rendered":"http:\/\/robot.tanxiaodian.com\/?p=173"},"modified":"2019-07-15T10:29:10","modified_gmt":"2019-07-15T02:29:10","slug":"173","status":"publish","type":"post","link":"https:\/\/log.tanxiaodian.com\/?p=173","title":{"rendered":"\u89e3\u91ca\u51fd\u6570explain"},"content":{"rendered":"

\u8f6c https:\/\/blog.csdn.net\/zhujuntiankong\/article\/details\/88118037
\n\u8f6c https:\/\/blog.csdn.net\/dennis211\/article\/details\/78170079 type\u53c2\u6570\u7684\u610f\u4e49<\/p>\n

\u4f7f\u7528\u89e3\u91ca\u51fd\u6570explain\uff0c\u53ea\u9700\u6dfb\u52a0\u5728sql\u8bed\u53e5\u4e4b\u524d\u5373\u53ef\uff1a<\/p>\n

\u8868\u4e2d\u7684\u7d22\u5f15\uff1a<\/p>\n

\u67e5\u770bsql\u662f\u5426\u7528\u5230\u7d22\u5f15\uff1a<\/p>\n

\u6211\u4eec\u53ea\u9700\u8981\u6ce8\u610f\u4e00\u4e2a\u6700\u91cd\u8981\u7684type \u7684\u4fe1\u606f\u5f88\u660e\u663e\u7684\u63d0\u73b0\u662f\u5426\u7528\u5230\u7d22\u5f15\uff1a<\/p>\n

type\u7ed3\u679c\u503c\u4ece\u597d\u5230\u574f\u4f9d\u6b21\u662f\uff1a<\/p>\n

system > const > eq_ref > ref > fulltext > ref_or_null > index_merge > unique_subquery > index_subquery > range > index > ALL<\/p>\n

\u4e00\u822c\u6765\u8bf4\uff0c\u5f97\u4fdd\u8bc1\u67e5\u8be2\u81f3\u5c11\u8fbe\u5230range\u7ea7\u522b\uff0c\u6700\u597d\u80fd\u8fbe\u5230ref\uff0c\u5426\u5219\u5c31\u53ef\u80fd\u4f1a\u51fa\u73b0\u6027\u80fd\u95ee\u9898\u3002<\/p>\n

possible_keys\uff1asql\u6240\u7528\u5230\u7684\u7d22\u5f15<\/p>\n

key\uff1a\u663e\u793aMySQL\u5b9e\u9645\u51b3\u5b9a\u4f7f\u7528\u7684\u952e\uff08\u7d22\u5f15\uff09\u3002\u5982\u679c\u6ca1\u6709\u9009\u62e9\u7d22\u5f15\uff0c\u952e\u662fNULL<\/p>\n

rows: \u663e\u793aMySQL\u8ba4\u4e3a\u5b83\u6267\u884c\u67e5\u8be2\u65f6\u5fc5\u987b\u68c0\u67e5\u7684\u884c\u6570\u3002<\/p>\n

\u00a0<\/p>\n

\u6ce8\u610f\uff1a \u5982\u9047\u5230\u5b57\u6bb5\u592a\u957f\uff0c\u6dfb\u52a0\u4e0d\u4e86\u7d22\u5f15\uff0c\u800c\u53c8\u4e0d\u80fd\u51cf\u5c0f\u5b57\u6bb5\u957f\u5ea6\uff0c\u5219\u53ef\u4ee5\u9700\u8981\u6307\u5b9a\u7d22\u5f15\u957f\u5ea6\u3002<\/p>\n

\u5982\uff1a<\/p>\n

CREATE\u00a0\u00a0INDEX\u00a0 \u7d22\u5f15\u540d\u79f0\u00a0 ON\u00a0 \u8868\u540d\u00a0 (\u5b57\u6bb5\u540d(size)) ;<\/p>\n

CREATE\u00a0 INDEX\u00a0 \u00a0IDX_ELEMENT_XXX\u00a0 ON\u00a0 table_element (xxx_id(200)) ;<\/p>\n

\u7ed9table_element\u8868\u4e2d\u7684xxx_id\u5b57\u6bb5\u6dfb\u52a0\u6307\u5b9a200\u957f\u5ea6\u7684\u7d22\u5f15IDX_ELEMENT_XXX<\/p>\n","protected":false},"excerpt":{"rendered":"

\u8f6c https:\/\/blog.csdn.net\/z…<\/p>\n

Continue reading\u89e3\u91ca\u51fd\u6570explain<\/span><\/a><\/div>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":[],"categories":[2],"tags":[],"_links":{"self":[{"href":"https:\/\/log.tanxiaodian.com\/index.php?rest_route=\/wp\/v2\/posts\/173"}],"collection":[{"href":"https:\/\/log.tanxiaodian.com\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/log.tanxiaodian.com\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/log.tanxiaodian.com\/index.php?rest_route=\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/log.tanxiaodian.com\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=173"}],"version-history":[{"count":3,"href":"https:\/\/log.tanxiaodian.com\/index.php?rest_route=\/wp\/v2\/posts\/173\/revisions"}],"predecessor-version":[{"id":176,"href":"https:\/\/log.tanxiaodian.com\/index.php?rest_route=\/wp\/v2\/posts\/173\/revisions\/176"}],"wp:attachment":[{"href":"https:\/\/log.tanxiaodian.com\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=173"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/log.tanxiaodian.com\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=173"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/log.tanxiaodian.com\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=173"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}