{"id":6418,"date":"2024-11-14T13:06:29","date_gmt":"2024-11-14T05:06:29","guid":{"rendered":"https:\/\/fwq.ai\/blog\/6418\/"},"modified":"2024-11-14T13:06:29","modified_gmt":"2024-11-14T05:06:29","slug":"mysql%e6%9f%a5%e7%9c%8b%e7%b4%a2%e5%bc%95%e5%91%bd%e4%bb%a4","status":"publish","type":"post","link":"https:\/\/fwq.ai\/blog\/6418\/","title":{"rendered":"mysql\u67e5\u770b\u7d22\u5f15\u547d\u4ee4"},"content":{"rendered":"

\n mysql \u4e2d\u53ef\u4ee5\u901a\u8fc7\u4ee5\u4e0b\u65b9\u5f0f\u67e5\u770b\u7d22\u5f15\u4fe1\u606f\uff1ashow index\uff1a\u663e\u793a\u7d22\u5f15\u5b9a\u4e49\uff1bexplain\uff1a\u5206\u6790\u67e5\u8be2\u5e76\u663e\u793a\u7d22\u5f15\u4f7f\u7528\u60c5\u51b5\uff1binformation_schema \u8868\uff1a\u5305\u542b\u7d22\u5f15\u7684\u5143\u6570\u636e\uff0c\u53ef\u901a\u8fc7\u67e5\u8be2\u83b7\u53d6\u7edf\u8ba1\u4fe1\u606f\u3002\n<\/p><\/blockquote>\n

\"mysql\u67e5\u770b\u7d22\u5f15\u547d\u4ee4\u63d2\u56fe\"<\/p>\n

\u5982\u4f55\u4f7f\u7528 MySQL \u67e5\u770b\u7d22\u5f15<\/strong><\/p>\n

\u4e86\u89e3\u6570\u636e\u5e93\u4e2d\u8868\u7684\u7d22\u5f15\u60c5\u51b5\u5bf9\u4e8e\u63d0\u9ad8\u67e5\u8be2\u6027\u80fd\u81f3\u5173\u91cd\u8981\u3002MySQL \u63d0\u4f9b\u4e86\u591a\u79cd\u547d\u4ee4\u6765\u67e5\u770b\u7d22\u5f15\u4fe1\u606f\uff0c\u5305\u62ec\uff1a<\/p>\n

1. SHOW INDEX<\/strong><\/p>\n

SHOW INDEX \u547d\u4ee4\u663e\u793a\u8868\u7684\u7d22\u5f15\u5b9a\u4e49\u3002\u5bf9\u4e8e\u8868 my_table\uff0c\u547d\u4ee4\u5982\u4e0b\uff1a<\/p>\n

SHOW INDEX FROM my_table;<\/pre>\n
 \u767b\u5f55\u540e\u590d\u5236 <\/p>\n
\u8fd9\u4f1a\u8f93\u51fa\u4e00\u4e2a\u5305\u542b\u4ee5\u4e0b\u4fe1\u606f\u7684\u8868\uff1a<\/p>\n
    \n
  • Index_Name\uff1a\u7d22\u5f15\u7684\u540d\u79f0\u3002<\/li>\n
  • Column_Name\uff1a\u7d22\u5f15\u7684\u5217\u3002<\/li>\n
  • Sub_part\uff1a\u5217\u7684\u524d\u7f00\u957f\u5ea6\uff08\u4ec5\u9002\u7528\u4e8e\u524d\u7f00\u7d22\u5f15\uff09\u3002<\/li>\n
  • Non_unique\uff1a\u662f\u5426\u552f\u4e00\u7d22\u5f15\u3002<\/li>\n
  • Index_type\uff1a\u7d22\u5f15\u7c7b\u578b\uff08\u5982 BTREE\u3001HASH\uff09\u3002<\/li>\n
  • Comment\uff1a\u7d22\u5f15\u7684\u53ef\u9009\u6ce8\u91ca\u3002<\/li>\n<\/ul>\n
    2. EXPLAIN<\/strong><\/p>\n
    EXPLAIN \u547d\u4ee4\u5206\u6790\u67e5\u8be2\u5e76\u663e\u793a\u6267\u884c\u8ba1\u5212\u3002\u5176\u4e2d\u5305\u542b\u6709\u5173\u7d22\u5f15\u4f7f\u7528\u7684\u4fe1\u606f\u3002\u5bf9\u4e8e\u67e5\u8be2 SELECT * FROM my_table WHERE id = 1\uff0c\u547d\u4ee4\u5982\u4e0b\uff1a<\/p>\n
    EXPLAIN SELECT * FROM my_table WHERE id = 1;<\/pre>\n
     \u767b\u5f55\u540e\u590d\u5236 <\/p>\n
    \u8f93\u51fa\u5c06\u663e\u793a\u4ee5\u4e0b\u4fe1\u606f\uff0c\u5176\u4e2d\u5305\u62ec\u7d22\u5f15\u4f7f\u7528\u60c5\u51b5\uff1a<\/p>\n
      \n
    • id\uff1a\u8bed\u53e5\u7684\u552f\u4e00\u6807\u8bc6\u7b26\u3002<\/li>\n
    • select_type\uff1a\u67e5\u8be2\u7c7b\u578b\u3002<\/li>\n
    • table\uff1a\u6d89\u53ca\u7684\u8868\u3002<\/li>\n
    • type\uff1a\u8fde\u63a5\u7c7b\u578b\u3002<\/li>\n
    • possible_keys\uff1a\u67e5\u8be2\u53ef\u80fd\u4f7f\u7528\u7684\u7d22\u5f15\u3002<\/li>\n
    • key\uff1a\u5b9e\u9645\u4f7f\u7528\u7684\u7d22\u5f15\u3002<\/li>\n
    • key_len\uff1a\u4f7f\u7528\u7684\u7d22\u5f15\u957f\u5ea6\u3002<\/li>\n<\/ul>\n
      3. INFORMATION_SCHEMA \u8868<\/strong><\/p>\n
      MySQL \u7684 INFORMATION_SCHEMA \u6570\u636e\u5e93\u5305\u542b\u6709\u5173\u6570\u636e\u5e93\u5bf9\u8c61\u7684\u5143\u6570\u636e\u3002\u4ee5\u4e0b\u8868\u63d0\u4f9b\u4e86\u7d22\u5f15\u4fe1\u606f\uff1a<\/p>\n
        \n
      • TABLE_STATISTICS\uff1a\u603b\u4f53\u7d22\u5f15\u7edf\u8ba1\u4fe1\u606f\uff0c\u5305\u62ec\u8868\u3001\u7d22\u5f15\u540d\u79f0\u548c\u7d22\u5f15\u5927\u5c0f\u3002<\/li>\n
      • KEY_COLUMN_USAGE\uff1a\u7d22\u5f15\u5217\u8be6\u7ec6\u4fe1\u606f\uff0c\u5305\u62ec\u8868\u3001\u7d22\u5f15\u540d\u79f0\u3001\u5217\u548c\u7d22\u5f15\u7c7b\u578b\u3002<\/li>\n<\/ul>\n
        \u901a\u8fc7\u67e5\u8be2\u8fd9\u4e9b\u8868\uff0c\u60a8\u53ef\u4ee5\u83b7\u53d6\u6709\u5173\u7d22\u5f15\u7684\u8be6\u7ec6\u7edf\u8ba1\u4fe1\u606f\uff0c\u4f8b\u5982\uff1a<\/p>\n
        SELECT table_name, index_name, cardinality, data_length\nFROM INFORMATION_SCHEMA.STATISTICS\nWHERE table_schema = 'my_schema'\nAND table_name = 'my_table';<\/pre>\n
         \u767b\u5f55\u540e\u590d\u5236 <\/p>\n
        \u901a\u8fc7\u4f7f\u7528\u8fd9\u4e9b\u547d\u4ee4\u548c\u8868\uff0c\u60a8\u53ef\u4ee5\u8f7b\u677e\u67e5\u770b MySQL \u4e2d\u8868\u7684\u7d22\u5f15\u4fe1\u606f\uff0c\u4ee5\u4fbf\u4f18\u5316\u67e5\u8be2\u6027\u80fd\u3002<\/p>\n
        \u4ee5\u4e0a\u5c31\u662f\u67e5\u770b\u7d22\u5f15\u547d\u4ee4\u7684\u8be6\u7ec6\u5185\u5bb9\uff0c\u66f4\u591a\u8bf7\u5173\u6ce8\u7c73\u4e91\u7f51\u5176\u5b83\u76f8\u5173\u6587\u7ae0\uff01<\/p>\n","protected":false},"excerpt":{"rendered":"
        mysql \u4e2d\u53ef\u4ee5\u901a\u8fc7\u4ee5\u4e0b\u65b9\u5f0f\u67e5\u770b\u7d22\u5f15\u4fe1\u606f\uff1ashow index\uff1a\u663e\u793a\u7d22\u5f15\u5b9a\u4e49\uff1bexplain\uff1a\u5206\u6790\u67e5\u8be2\u5e76\u663e\u793a\u7d22\u5f15\u4f7f\u7528\u60c5\u51b5\uff1binformation_schema \u8868\uff1a\u5305\u542b\u7d22\u5f15\u7684\u5143\u6570\u636e\uff0c\u53ef\u901a\u8fc7\u67e5\u8be2\u83b7\u53d6\u7edf\u8ba1\u4fe1\u606f\u3002 \u5982\u4f55\u4f7f\u7528 MySQL \u67e5\u770b\u7d22\u5f15 \u4e86\u89e3\u6570\u636e\u5e93\u4e2d\u8868\u7684\u7d22\u5f15\u60c5\u51b5\u5bf9\u4e8e\u63d0\u9ad8\u67e5\u8be2\u6027\u80fd\u81f3\u5173\u91cd\u8981\u3002MySQL \u63d0\u4f9b\u4e86\u591a\u79cd\u547d\u4ee4\u6765\u67e5\u770b\u7d22\u5f15\u4fe1\u606f\uff0c\u5305\u62ec\uff1a 1. SHOW INDEX SHOW INDEX \u547d\u4ee4\u663e\u793a\u8868\u7684\u7d22\u5f15\u5b9a\u4e49\u3002\u5bf9\u4e8e\u8868 my_table\uff0c\u547d\u4ee4\u5982\u4e0b\uff1a SHOW INDEX FROM my_table; \u767b\u5f55\u540e\u590d\u5236 \u8fd9\u4f1a\u8f93\u51fa\u4e00\u4e2a\u5305\u542b\u4ee5\u4e0b\u4fe1\u606f\u7684\u8868\uff1a Index_Name\uff1a\u7d22\u5f15\u7684\u540d\u79f0\u3002 Column_Name\uff1a\u7d22\u5f15\u7684\u5217\u3002 Sub_part\uff1a\u5217\u7684\u524d\u7f00\u957f\u5ea6\uff08\u4ec5\u9002\u7528\u4e8e\u524d\u7f00\u7d22\u5f15\uff09\u3002 Non_unique\uff1a\u662f\u5426\u552f\u4e00\u7d22\u5f15\u3002 Index_type\uff1a\u7d22\u5f15\u7c7b\u578b\uff08\u5982 BTREE\u3001HASH\uff09\u3002 Comment\uff1a\u7d22\u5f15\u7684\u53ef\u9009\u6ce8\u91ca\u3002 2. EXPLAIN EXPLAIN \u547d\u4ee4\u5206\u6790\u67e5\u8be2\u5e76\u663e\u793a\u6267\u884c\u8ba1\u5212\u3002\u5176\u4e2d\u5305\u542b\u6709\u5173\u7d22\u5f15\u4f7f\u7528\u7684\u4fe1\u606f\u3002\u5bf9\u4e8e\u67e5\u8be2 SELECT * FROM my_table WHERE id = 1\uff0c\u547d\u4ee4\u5982\u4e0b\uff1a EXPLAIN SELECT * FROM my_table WHERE id = 1; \u767b\u5f55\u540e\u590d\u5236 \u8f93\u51fa\u5c06\u663e\u793a\u4ee5\u4e0b\u4fe1\u606f\uff0c\u5176\u4e2d\u5305\u62ec\u7d22\u5f15\u4f7f\u7528\u60c5\u51b5\uff1a id\uff1a\u8bed\u53e5\u7684\u552f\u4e00\u6807\u8bc6\u7b26\u3002 select_type\uff1a\u67e5\u8be2\u7c7b\u578b\u3002 table\uff1a\u6d89\u53ca\u7684\u8868\u3002 […]<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"closed","ping_status":"","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[16],"tags":[],"class_list":["post-6418","post","type-post","status-publish","format-standard","hentry","category-16"],"_links":{"self":[{"href":"https:\/\/fwq.ai\/blog\/wp-json\/wp\/v2\/posts\/6418","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/fwq.ai\/blog\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/fwq.ai\/blog\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/fwq.ai\/blog\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/fwq.ai\/blog\/wp-json\/wp\/v2\/comments?post=6418"}],"version-history":[{"count":0,"href":"https:\/\/fwq.ai\/blog\/wp-json\/wp\/v2\/posts\/6418\/revisions"}],"wp:attachment":[{"href":"https:\/\/fwq.ai\/blog\/wp-json\/wp\/v2\/media?parent=6418"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/fwq.ai\/blog\/wp-json\/wp\/v2\/categories?post=6418"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/fwq.ai\/blog\/wp-json\/wp\/v2\/tags?post=6418"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}