{"id":200591,"date":"2025-05-06T11:05:21","date_gmt":"2025-05-06T03:05:21","guid":{"rendered":"https:\/\/server.hk\/cnblog\/200591\/"},"modified":"2025-05-06T11:05:21","modified_gmt":"2025-05-06T03:05:21","slug":"mysql-%e5%88%a0%e9%99%a4%e6%95%b0%e6%8d%ae%e4%bc%9a%e4%bd%bf%e7%94%a8%e7%b4%a2%e5%bc%95%e5%90%97%ef%bc%9f","status":"publish","type":"post","link":"https:\/\/server.hk\/cnblog\/200591\/","title":{"rendered":"MySQL \u5220\u9664\u6570\u636e\u4f1a\u4f7f\u7528\u7d22\u5f15\u5417\uff1f"},"content":{"rendered":"<p><b><\/b> <\/p>\n<h1>MySQL \u5220\u9664\u6570\u636e\u4f1a\u4f7f\u7528\u7d22\u5f15\u5417\uff1f<\/h1>\n<p>\u4e0d\u77e5\u9053\u5927\u5bb6\u662f\u5426\u719f\u6089\uff1f\u4eca\u5929\u6211\u5c06\u7ed9\u5927\u5bb6\u4ecb\u7ecd\uff0c\u8fd9\u7bc7\u6587\u7ae0\u4e3b\u8981\u4f1a\u8bb2\u5230\u7b49\u7b49\u77e5\u8bc6\u70b9\uff0c\u5982\u679c\u4f60\u5728\u770b\u5b8c\u672c\u7bc7\u6587\u7ae0\u540e\uff0c\u6709\u66f4\u597d\u7684\u5efa\u8bae\u6216\u8005\u53d1\u73b0\u54ea\u91cc\u6709\u95ee\u9898\uff0c\u5e0c\u671b\u5927\u5bb6\u90fd\u80fd\u79ef\u6781\u8bc4\u8bba\u6307\u51fa\uff0c\u8c22\u8c22\uff01\u5e0c\u671b\u6211\u4eec\u80fd\u4e00\u8d77\u52a0\u6cb9\u8fdb\u6b65\uff01<\/p>\n<p><img decoding=\"async\" src=\"https:\/\/www.17golang.com\/uploads\/20241109\/1731122674672ed5f24d1ea.jpg\" class=\"aligncenter\"><\/p>\n<p><strong>mysql \u5220\u9664\u6570\u636e\u662f\u5426\u8d70\u7d22\u5f15<\/strong><\/p>\n<p>\u5728 mysql \u4e2d\uff0c\u5f53\u9700\u8981\u5220\u9664\u5927\u91cf\u6570\u636e\u65f6\uff0c\u662f\u5426\u91c7\u7528\u7d22\u5f15\u662f\u4e00\u4e2a\u503c\u5f97\u5173\u6ce8\u7684\u95ee\u9898\u3002\u672c\u6587\u5c06\u63a2\u8ba8\u4ee5\u4e0b\u95ee\u9898\uff1a<\/p>\n<p><strong>\u5982\u679c\u6211\u60f3\u5220\u9664\u6ee1\u8db3\u67d0\u4e9b\u6761\u4ef6\u7684\u6570\u636e\uff0c\u4f8b\u5982 sex=\u7537\u3001city=\u5317\u4eac\uff0cmysql \u7d22\u5f15\u662f\u5426\u4f1a\u88ab\u4f7f\u7528\uff1f<\/strong><\/p>\n<p>\u4e3a\u4e86\u56de\u7b54\u8fd9\u4e2a\u95ee\u9898\uff0c\u6211\u4eec\u9700\u8981\u4e86\u89e3 mysql \u5220\u9664\u6570\u636e\u7684\u673a\u5236\uff1a<\/p>\n<ul>\n<li><strong>\u7d22\u5f15\u7684\u4f7f\u7528\u6761\u4ef6\uff1a<\/strong>\u5f53\u8981\u5220\u9664\u7684\u6570\u636e\u91cf\u5360\u8868\u6570\u636e\u7684 20% \u4ee5\u4e0a\u65f6\uff0cmysql \u624d\u4f1a\u4f7f\u7528\u7d22\u5f15\u3002<\/li>\n<li><strong>\u6761\u4ef6\u5339\u914d\uff1a<\/strong>\u7d22\u5f15\u4f1a\u88ab\u7528\u4e8e\u5339\u914d\u5220\u9664\u6761\u4ef6\u3002\u4f8b\u5982\uff0c\u5728\u4f60\u7684\u6848\u4f8b\u4e2d\uff0c\u5982\u679c\u6ee1\u8db3 sex=\u7537 \u548c city=\u5317\u4eac \u6761\u4ef6\u7684\u6570\u636e\u91cf\u8d85\u8fc7\u8868\u6570\u636e\u7684 20%\uff0c\u90a3\u4e48\u7d22\u5f15 (sex, city) \u5c06\u4f1a\u88ab\u4f7f\u7528\u3002<\/li>\n<\/ul>\n<p><strong>\u5b9e\u9645\u64cd\u4f5c\u793a\u4f8b\uff1a<\/strong><\/p>\n<p>\u5047\u8bbe\u6709\u4e00\u5f20\u540d\u4e3a test_del_idx \u7684\u8868\uff0c\u5305\u542b\u4ee5\u4e0b\u5b57\u6bb5\uff1aid\u3001name\u3001age\u3001sex\u3001work\u3001city\uff0c\u5e76\u4e14\u6709\u8054\u5408\u7d22\u5f15 (sex, city)\u3002<\/p>\n<p><strong>\u5f53\u8981\u5220\u9664\u6ee1\u8db3 sex=\u5973\u3001city=\u5e7f\u5dde \u6761\u4ef6\u7684\u6570\u636e\u65f6\uff1a<\/strong><\/p>\n<pre>explain delete from test_del_idx where sex=\"\u5973\" and city = \"\u5e7f\u5dde\";<\/pre>\n<p>\u8f93\u51fa\u4fe1\u606f\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>\u53ef\u4ee5\u770b\u5230\uff0cmysql \u6ca1\u6709\u4f7f\u7528\u7d22\u5f15\u8fdb\u884c\u5220\u9664\uff0c\u56e0\u4e3a\u6ee1\u8db3\u6761\u4ef6\u7684\u6570\u636e\u91cf\u4ec5\u5360\u8868\u6570\u636e\u7684 37.68%\u3002<\/p>\n<p><strong>\u5f53\u8981\u5220\u9664\u6ee1\u8db3 sex=\u5973\u3001city=\u60e0\u5dde \u6761\u4ef6\u7684\u6570\u636e\u65f6\uff1a<\/strong><\/p>\n<pre>explain delete from test_del_idx where sex=\"\u5973\" and city = \"\u60e0\u5dde\";<\/pre>\n<p>\u8f93\u51fa\u4fe1\u606f\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>\u53ef\u4ee5\u770b\u5230\uff0cmysql \u4f7f\u7528\u4e86\u7d22\u5f15 \u8fdb\u884c\u5220\u9664\uff0c\u56e0\u4e3a\u6ee1\u8db3\u6761\u4ef6\u7684\u6570\u636e\u91cf\u4ec5\u5360\u8868\u6570\u636e\u7684 0.38%\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\u4f1a\u4f7f\u7528\u7d22\u5f15\u5417\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\u4f1a\u4f7f\u7528\u7d22\u5f15\u5417&#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-200591","post","type-post","status-publish","format-standard","hentry","category-database"],"_links":{"self":[{"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/posts\/200591","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=200591"}],"version-history":[{"count":0,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/posts\/200591\/revisions"}],"wp:attachment":[{"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/media?parent=200591"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/categories?post=200591"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/tags?post=200591"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}