{"id":200274,"date":"2025-05-06T09:19:35","date_gmt":"2025-05-06T01:19:35","guid":{"rendered":"https:\/\/server.hk\/cnblog\/200274\/"},"modified":"2025-05-06T09:19:35","modified_gmt":"2025-05-06T01:19:35","slug":"mysql-join-%e4%b8%b4%e6%97%b6%e8%a1%a8%e4%b8%ad%e5%8c%85%e5%90%ab%e5%93%aa%e4%ba%9b%e5%ad%97%e6%ae%b5%ef%bc%9f","status":"publish","type":"post","link":"https:\/\/server.hk\/cnblog\/200274\/","title":{"rendered":"MySQL JOIN \u4e34\u65f6\u8868\u4e2d\u5305\u542b\u54ea\u4e9b\u5b57\u6bb5\uff1f"},"content":{"rendered":"<p><b><\/b> <\/p>\n<h1>MySQL JOIN \u4e34\u65f6\u8868\u4e2d\u5305\u542b\u54ea\u4e9b\u5b57\u6bb5\uff1f<\/h1>\n<p>\u5bf9\u4e8e\u4e00\u4e2a\u6570\u636e\u5e93\u5f00\u53d1\u8005\u6765\u8bf4\uff0c\u7262\u56fa\u624e\u5b9e\u7684\u57fa\u7840\u662f\u5341\u5206\u91cd\u8981\u7684\uff0c\u4e3b\u673a\u5b9d\u8d1d\u5c31\u6765\u5e26\u5927\u5bb6\u4e00\u70b9\u70b9\u7684\u638c\u63e1\u57fa\u7840\u77e5\u8bc6\u70b9\u3002\u4eca\u5929\u672c\u7bc7\u6587\u7ae0\u5e26\u5927\u5bb6\u4e86\u89e3\u300aMySQL JOIN \u4e34\u65f6\u8868\u4e2d\u5305\u542b\u54ea\u4e9b\u5b57\u6bb5\uff1f\u300b\uff0c\u4e3b\u8981\u4ecb\u7ecd\u4e86\uff0c\u5e0c\u671b\u5bf9\u5927\u5bb6\u7684\u77e5\u8bc6\u79ef\u7d2f\u6709\u6240\u5e2e\u52a9\uff0c\u5feb\u70b9\u6536\u85cf\u8d77\u6765\u5427\uff0c\u5426\u5219\u9700\u8981\u65f6\u5c31\u627e\u4e0d\u5230\u4e86\uff01<\/p>\n<p><img decoding=\"async\" src=\"https:\/\/www.17golang.com\/uploads\/20241031\/17303351876722d1d3d499c.jpg\" class=\"aligncenter\"><\/p>\n<p><strong>MySQL JOIN \u4e34\u65f6\u8868\u7684\u5b57\u6bb5\u95ee\u9898<\/strong><\/p>\n<p>\u6570\u636e\u5e93\u4e2d\u6267\u884c JOIN \u64cd\u4f5c\u65f6\uff0c\u4e3a\u4e86\u63d0\u9ad8\u67e5\u8be2\u6548\u7387\uff0cMySQL \u4f1a\u751f\u6210\u4e34\u65f6\u8868\u3002\u5728\u8868 A \u548c\u8868 B \u8fdb\u884c JOIN \u64cd\u4f5c\u540e\u4ea7\u751f\u7684\u4e34\u65f6\u8868\u4f1a\u5305\u542b\u54ea\u4e9b\u5b57\u6bb5\uff0c\u8fd9\u662f\u4e00\u4e2a\u503c\u5f97\u63a2\u8ba8\u7684\u95ee\u9898\u3002<\/p>\n<p>\u5047\u8bbe\u8868 A \u548c\u8868 B \u90fd\u6709 4 \u4e2a\u5b57\u6bb5\uff0c\u5982\u95ee\u9898\u63cf\u8ff0\u6240\u793a\u3002\u95ee\u9898\u4e2d\u7ed9\u51fa\u4e86\u4e00\u4e2a SQL \u67e5\u8be2\u793a\u4f8b\uff0c\u5176\u4e2d\u4f7f\u7528\u4e86 INNER JOIN \u8fde\u63a5\u8868 A \u548c\u8868 B\u3002<\/p>\n<p>\u90a3\u4e48\uff0c\u751f\u6210\u7684\u4e34\u65f6\u8868\u662f M \u8fd8\u662f N \u5462\uff1f<\/p>\n<p><strong>\u4e34\u65f6\u8868 N<\/strong><\/p>\n<p>\u7b54\u6848\u662f N\u3002 temporary table N \u7684\u7ed3\u6784\u5982\u4e0b\uff1a<\/p>\n<table>\n<thead>\n<tr>\n<th>\u5217\u540d<\/th>\n<th>\u6570\u636e\u7c7b\u578b<\/th>\n<\/tr>\n<\/thead>\n<tbody>\n<tr>\n<td>A.id<\/td>\n<td>\u4e0e\u8868 A \u4e2d\u7684 id \u5217\u76f8\u540c<\/td>\n<\/tr>\n<tr>\n<td>A.name<\/td>\n<td>\u4e0e\u8868 A \u4e2d\u7684 name \u5217\u76f8\u540c<\/td>\n<\/tr>\n<tr>\n<td>A.status<\/td>\n<td>\u4e0e\u8868 A \u4e2d\u7684 status \u5217\u76f8\u540c<\/td>\n<\/tr>\n<tr>\n<td>A.delete_sign<\/td>\n<td>\u4e0e\u8868 A \u4e2d\u7684 delete_sign \u5217\u76f8\u540c<\/td>\n<\/tr>\n<tr>\n<td>B.delete_sign<\/td>\n<td>\u4e0e\u8868 B \u4e2d\u7684 delete_sign \u5217\u76f8\u540c<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<p><strong>\u4e3a\u4ec0\u4e48\u662f N\uff1f<\/strong><\/p>\n<p>\u539f\u56e0\u5728\u4e8e\uff0cINNER JOIN \u4ec5\u4fdd\u7559\u6ee1\u8db3\u8fde\u63a5\u6761\u4ef6\u7684\u884c\u3002\u5728\u672c\u4f8b\u4e2d\uff0c\u8fde\u63a5\u6761\u4ef6\u662f a.id = b.a_id\u3002\u56e0\u6b64\uff0c\u4e34\u65f6\u8868\u4ec5\u9700\u8981\u5305\u542b\u6ee1\u8db3\u6b64\u6761\u4ef6\u7684\u884c\uff0c\u800c\u4e0d\u9700\u8981\u5305\u542b\u8868 B \u7684\u5176\u4ed6\u5b57\u6bb5\u3002<\/p>\n<p>\u53e6\u4e00\u65b9\u9762\uff0c\u4e34\u65f6\u8868 M \u5305\u542b\u4e86\u8868 A \u548c\u8868 B \u7684\u6240\u6709\u5b57\u6bb5\u3002\u8fd9\u5728\u5b9e\u9645\u9879\u76ee\u4e2d\u53ef\u80fd\u5bfc\u81f4\u6027\u80fd\u95ee\u9898\uff0c\u5c24\u5176\u662f\u5f53\u8868\u4e2d\u5b57\u6bb5\u8f83\u591a\u65f6\u3002<\/p>\n<p>\u56e0\u6b64\uff0c\u5728\u8fdb\u884c JOIN \u64cd\u4f5c\u65f6\uff0c\u4e34\u65f6\u8868\u7684\u5b57\u6bb5\u5185\u5bb9\u7531 JOIN \u7c7b\u578b\u548c\u8fde\u63a5\u6761\u4ef6\u51b3\u5b9a\u3002\u5728\u5927\u591a\u6570\u60c5\u51b5\u4e0b\uff0c\u4e34\u65f6\u8868\u4f1a\u5305\u542b\u6ee1\u8db3\u8fde\u63a5\u6761\u4ef6\u7684\u5217\uff0c\u5c31\u50cf\u4e34\u65f6\u8868 N \u6240\u793a\u7684\u90a3\u6837\u3002<\/p>\n<p>\u4ee5\u4e0a\u5c31\u662f\u300aMySQL JOIN \u4e34\u65f6\u8868\u4e2d\u5305\u542b\u54ea\u4e9b\u5b57\u6bb5\uff1f\u300b\u7684\u8be6\u7ec6\u5185\u5bb9\uff0c\u66f4\u591a\u5173\u4e8e\u7684\u8d44\u6599\u8bf7\u5173\u6ce8\u4e3b\u673a\u5b9d\u8d1d\u516c\u4f17\u53f7\uff01<\/p>\n<dl>\n<dt>\n <\/dt>\n<\/dl>\n","protected":false},"excerpt":{"rendered":"<p>MySQL JOIN \u4e34\u65f6\u8868\u4e2d\u5305&#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-200274","post","type-post","status-publish","format-standard","hentry","category-database"],"_links":{"self":[{"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/posts\/200274","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=200274"}],"version-history":[{"count":0,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/posts\/200274\/revisions"}],"wp:attachment":[{"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/media?parent=200274"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/categories?post=200274"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/tags?post=200274"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}