{"id":200407,"date":"2025-05-06T12:08:03","date_gmt":"2025-05-06T04:08:03","guid":{"rendered":"https:\/\/server.hk\/cnblog\/200407\/"},"modified":"2025-05-06T12:08:03","modified_gmt":"2025-05-06T04:08:03","slug":"mysql-%e5%88%a0%e9%99%a4%e6%95%b0%e6%8d%ae%e6%97%b6%e6%98%af%e5%90%a6%e4%bc%9a%e5%88%a9%e7%94%a8%e7%b4%a2%e5%bc%95%ef%bc%9f","status":"publish","type":"post","link":"https:\/\/server.hk\/cnblog\/200407\/","title":{"rendered":"MySQL \u5220\u9664\u6570\u636e\u65f6\u662f\u5426\u4f1a\u5229\u7528\u7d22\u5f15\uff1f"},"content":{"rendered":"<p><b><\/b> <\/p>\n<h1>MySQL \u5220\u9664\u6570\u636e\u65f6\u662f\u5426\u4f1a\u5229\u7528\u7d22\u5f15\uff1f<\/h1>\n<p>\u600e\u4e48\u5165\u95e8\u6570\u636e\u5e93\u7f16\u7a0b\uff1f\u9700\u8981\u5b66\u4e60\u54ea\u4e9b\u77e5\u8bc6\u70b9\uff1f\u8fd9\u662f\u65b0\u624b\u4eec\u521a\u63a5\u89e6\u7f16\u7a0b\u65f6\u5e38\u89c1\u7684\u95ee\u9898\uff1b\u4e0b\u9762\u4e3b\u673a\u5b9d\u8d1d\u5c31\u6765\u7ed9\u5927\u5bb6\u6574\u7406\u5206\u4eab\u4e00\u4e9b\u77e5\u8bc6\u70b9\uff0c\u5e0c\u671b\u80fd\u591f\u7ed9\u521d\u5b66\u8005\u4e00\u4e9b\u5e2e\u52a9\u3002\u672c\u7bc7\u6587\u7ae0\u5c31\u6765\u4ecb\u7ecd\u300aMySQL \u5220\u9664\u6570\u636e\u65f6\u662f\u5426\u4f1a\u5229\u7528\u7d22\u5f15\uff1f\u300b\uff0c\u6d89\u53ca\u5230\uff0c\u6709\u9700\u8981\u7684\u53ef\u4ee5\u6536\u85cf\u4e00\u4e0b<\/p>\n<p><img decoding=\"async\" src=\"https:\/\/www.17golang.com\/uploads\/20241104\/17307039946728727a2cd90.jpg\" class=\"aligncenter\"><\/p>\n<p><strong>mysql \u5220\u9664\u6570\u636e\u65f6\u662f\u5426\u5229\u7528\u7d22\u5f15<\/strong><\/p>\n<p><strong>\u95ee\u9898\u63cf\u8ff0\uff1a<\/strong><\/p>\n<p>\u5728\u62e5\u6709 (sex, city) \u8054\u5408\u7d22\u5f15\u7684 user \u8868\u4e2d\uff0c\u5220\u9664\u6307\u5b9a\u6027\u522b\u548c\u57ce\u5e02\u7684\u6570\u636e\u65f6\uff0c\u662f\u5426\u4f1a\u4f7f\u7528\u8be5\u7d22\u5f15\uff1f<\/p>\n<p><strong>\u7b54\u6848\uff1a<\/strong><\/p>\n<p>\u5728 mysql \u4e2d\uff0c\u5982\u679c\u5220\u9664\u64cd\u4f5c\u6d89\u53ca\u7684\u6570\u636e\u91cf\u8d85\u8fc7 20%\uff0c\u5c06\u4e0d\u4f1a\u4f7f\u7528\u7d22\u5f15\u3002\u5426\u5219\uff0c\u4f1a\u4f7f\u7528\u7d22\u5f15\u3002<\/p>\n<p><strong>\u5b9e\u8df5\u9a8c\u8bc1\uff1a<\/strong><\/p>\n<p>\u5047\u8bbe\u6570\u636e\u603b\u91cf\u4e3a 1602\uff0c\u5220\u9664\u6ee1\u8db3 sex=&#8221;\u5973&#8221;\u3001city=&#8221;\u5e7f\u5dde&#8221; \u6761\u4ef6\u7684\u6570\u636e\uff0c\u6d89\u53ca\u6570\u636e\u91cf\u4e3a 604\u3002<\/p>\n<pre>explain delete from test_del_idx where sex=\"\u5973\" and city = \"\u5e7f\u5dde\";<\/pre>\n<p>\u6267\u884c\u7ed3\u679c\uff1a<\/p>\n<pre>+---------+---------+--------------+------------+------+---------------+------+---------+------+------+----------+-------------+\n| id      | select_type | table        | partitions | type | possible_keys | key  | key_len | ref  | rows | filtered | extra       |\n+---------+---------+--------------+------------+------+---------------+------+---------+------+------+----------+-------------+\n| 1       | delete      | test_del_idx | null       | all  | idx_sex_city  | null | null    | null | 1602 |   100.00 | using where |\n+---------+---------+--------------+------------+------+---------------+------+---------+------+------+----------+-------------+<\/pre>\n<p>\u7531\u4e8e\u5220\u9664\u6570\u636e\u91cf\u8d85\u8fc7\u4e86 20%\uff0c\u56e0\u6b64\u672a\u8d70\u7d22\u5f15\u3002<\/p>\n<p>\u518d\u5047\u8bbe\u5220\u9664\u6ee1\u8db3 sex=&#8221;\u5973&#8221;\u3001city=&#8221;\u60e0\u5dde&#8221; \u6761\u4ef6\u7684\u6570\u636e\uff0c\u6d89\u53ca\u6570\u636e\u91cf\u4e3a 6\u3002<\/p>\n<pre>explain delete from test_del_idx where sex=\"\u5973\" and city = \"\u60e0\u5dde\";<\/pre>\n<p>\u6267\u884c\u7ed3\u679c\uff1a<\/p>\n<pre>+---------+---------+--------------+------------+-------+---------------+--------------+---------+-------------+------+----------+-------------+\n| id      | select_type | table        | partitions | type  | possible_keys | key          | key_len | ref         | rows | filtered | Extra       |\n+---------+---------+--------------+------------+-------+---------------+--------------+---------+-------------+------+----------+-------------+\n| 1       | DELETE      | test_del_idx | NULL       | range | idx_sex_city  | idx_sex_city | 773     | const,const |    6 |   100.00 | Using where |\n+---------+---------+--------------+------------+-------+---------------+--------------+---------+-------------+------+----------+-------------+<\/pre>\n<p>\u7531\u4e8e\u5220\u9664\u6570\u636e\u91cf\u5c11\u4e8e 20%\uff0c\u56e0\u6b64\u8d70\u7d22\u5f15\u3002<\/p>\n<p>\u7406\u8bba\u8981\u638c\u63e1\uff0c\u5b9e\u64cd\u4e0d\u80fd\u843d\uff01\u4ee5\u4e0a\u5173\u4e8e\u300aMySQL \u5220\u9664\u6570\u636e\u65f6\u662f\u5426\u4f1a\u5229\u7528\u7d22\u5f15\uff1f\u300b\u7684\u8be6\u7ec6\u4ecb\u7ecd\uff0c\u5927\u5bb6\u90fd\u638c\u63e1\u4e86\u5427\uff01\u5982\u679c\u60f3\u8981\u7ee7\u7eed\u63d0\u5347\u81ea\u5df1\u7684\u80fd\u529b\uff0c\u90a3\u4e48\u5c31\u6765\u5173\u6ce8\u4e3b\u673a\u5b9d\u8d1d\u516c\u4f17\u53f7\u5427\uff01<\/p>\n<dl>\n<dt>\n <\/dt>\n<\/dl>\n","protected":false},"excerpt":{"rendered":"<p>MySQL \u5220\u9664\u6570\u636e\u65f6\u662f\u5426\u4f1a\u5229\u7528&#46;&#46;&#46;<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"closed","ping_status":"","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[101],"tags":[],"class_list":["post-200407","post","type-post","status-publish","format-standard","hentry","category-database"],"_links":{"self":[{"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/posts\/200407","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/comments?post=200407"}],"version-history":[{"count":0,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/posts\/200407\/revisions"}],"wp:attachment":[{"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/media?parent=200407"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/categories?post=200407"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/tags?post=200407"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}