{"id":200990,"date":"2025-05-06T15:07:15","date_gmt":"2025-05-06T07:07:15","guid":{"rendered":"https:\/\/server.hk\/cnblog\/200990\/"},"modified":"2025-05-06T15:07:15","modified_gmt":"2025-05-06T07:07:15","slug":"mysql-%e5%85%b3%e8%81%94%e8%a1%a8%e6%9f%a5%e8%af%a2%e7%96%91%e9%9a%be%e8%a7%a3%e6%9e%90%ef%bc%9a%e5%a6%82%e4%bd%95%e4%bb%8e-a-%e8%a1%a8%e5%92%8c-b-%e8%a1%a8%e4%b8%ad%e8%8e%b7%e5%8f%96%e7%89%b9","status":"publish","type":"post","link":"https:\/\/server.hk\/cnblog\/200990\/","title":{"rendered":"MySQL \u5173\u8054\u8868\u67e5\u8be2\u7591\u96be\u89e3\u6790\uff1a\u5982\u4f55\u4ece A \u8868\u548c B \u8868\u4e2d\u83b7\u53d6\u7279\u5b9a\u6761\u4ef6\u7684\u8bb0\u5f55\uff1f"},"content":{"rendered":"<p><b><\/b> <\/p>\n<h1>MySQL \u5173\u8054\u8868\u67e5\u8be2\u7591\u96be\u89e3\u6790\uff1a\u5982\u4f55\u4ece A \u8868\u548c B \u8868\u4e2d\u83b7\u53d6\u7279\u5b9a\u6761\u4ef6\u7684\u8bb0\u5f55\uff1f<\/h1>\n<p>\u672c\u7bc7\u6587\u7ae0\u5411\u5927\u5bb6\u4ecb\u7ecd\u300aMySQL \u5173\u8054\u8868\u67e5\u8be2\u7591\u96be\u89e3\u6790\uff1a\u5982\u4f55\u4ece A \u8868\u548c B \u8868\u4e2d\u83b7\u53d6\u7279\u5b9a\u6761\u4ef6\u7684\u8bb0\u5f55\uff1f\u300b\uff0c\u4e3b\u8981\u5305\u62ec\uff0c\u5177\u6709\u4e00\u5b9a\u7684\u53c2\u8003\u4ef7\u503c\uff0c\u9700\u8981\u7684\u670b\u53cb\u53ef\u4ee5\u53c2\u8003\u4e00\u4e0b\u3002<\/p>\n<p><img decoding=\"async\" src=\"https:\/\/www.17golang.com\/uploads\/20241124\/1732444596674301b4a592e.jpg\" class=\"aligncenter\"><\/p>\n<p><strong>mysql \u5173\u8054\u8868\u67e5\u8be2\u7591\u96be\u89e3\u6790<\/strong><\/p>\n<p><strong>\u95ee\u9898\uff1a<\/strong><\/p>\n<p>\u5982\u4f55\u4f7f\u7528 mysql \u67e5\u8be2\u4e24\u4e2a\u8868 a \u548c b\uff0c\u4ee5\u63d0\u53d6\u7b26\u5408\u7279\u5b9a\u6761\u4ef6\u7684\u8bb0\u5f55\uff1f<\/p>\n<p><strong>\u8be6\u7ec6\u8bf4\u660e\uff1a<\/strong><\/p>\n<p>\u8868 a \u7684\u7ed3\u6784\u5982\u4e0b\uff1a<\/p>\n<pre>a\n---------------------\n| id | outer_id | ... |\n---------------------\n| 1  | 1        | ... |\n| 2  | 1        | ... |\n| 3  | 2        | ... |\n| 4  | 4        | ... |\n| 5  | 6        | ... |\n| 6  | 10       | ... |<\/pre>\n<p>\u8868 b \u7684\u7ed3\u6784\u5982\u4e0b\uff1a<\/p>\n<pre>b\n---------------------\n| id | type | ... |\n---------------------\n| 1  | 99   | ... |\n| 2  | 0    | ... |\n| 3  | 99   | ... |\n| 4  | 1    | ... |\n| 5  | 3    | ... |\n| 6  | 99   | ... |<\/pre>\n<p>\u9700\u8981\u67e5\u8be2\u51fa\u8868 a \u7684\u4e24\u79cd\u6570\u636e\uff1a<\/p>\n<ol>\n<li>\u4f7f\u7528 a \u8868\u7684 outer_id \u5173\u8054 b \u8868\u7684 id\uff0c\u5982\u679c\u5b58\u5728\u5219 type \u4e0d\u80fd\u4e3a 99\uff0c\u5982\u679c\u4e0d\u5b58\u5728\u5219\u4fdd\u7559\u8be5\u6570\u636e\u3002<\/li>\n<li>b \u8868\u5b58\u5728\u4e14 type \u7b49\u4e8e 99\u3002<\/li>\n<\/ol>\n<p><strong>\u89e3\u7b54\uff1a<\/strong><\/p>\n<p><strong>\u67e5\u8be2 1\uff1a<\/strong><\/p>\n<pre>select a.*\nfrom a a\nleft join b b on b.id = a.outer_id\nwhere b.id is null\n   or (b.id is not null and b.type != 99)<\/pre>\n<p><strong>\u67e5\u8be2 2\uff1a<\/strong><\/p>\n<pre>SELECT a.*\nFROM A a\nINNER JOIN B b ON b.id = a.outer_id AND b.type = 99<\/pre>\n<p>\u5230\u8fd9\u91cc\uff0c\u6211\u4eec\u4e5f\u5c31\u8bb2\u5b8c\u4e86\u300aMySQL \u5173\u8054\u8868\u67e5\u8be2\u7591\u96be\u89e3\u6790\uff1a\u5982\u4f55\u4ece A \u8868\u548c B \u8868\u4e2d\u83b7\u53d6\u7279\u5b9a\u6761\u4ef6\u7684\u8bb0\u5f55\uff1f\u300b\u7684\u5185\u5bb9\u4e86\u3002\u4e2a\u4eba\u8ba4\u4e3a\uff0c\u57fa\u7840\u77e5\u8bc6\u7684\u5b66\u4e60\u548c\u5de9\u56fa\uff0c\u662f\u4e3a\u4e86\u66f4\u597d\u7684\u5c06\u5176\u8fd0\u7528\u5230\u9879\u76ee\u4e2d\uff0c\u6b22\u8fce\u5173\u6ce8\u4e3b\u673a\u5b9d\u8d1d\u516c\u4f17\u53f7\uff0c\u5e26\u4f60\u4e86\u89e3\u66f4\u591a\u5173\u4e8e\u7684\u77e5\u8bc6\u70b9\uff01<\/p>\n<dl>\n<dt>\n <\/dt>\n<\/dl>\n","protected":false},"excerpt":{"rendered":"<p>MySQL \u5173\u8054\u8868\u67e5\u8be2\u7591\u96be\u89e3\u6790\uff1a&#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-200990","post","type-post","status-publish","format-standard","hentry","category-database"],"_links":{"self":[{"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/posts\/200990","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=200990"}],"version-history":[{"count":0,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/posts\/200990\/revisions"}],"wp:attachment":[{"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/media?parent=200990"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/categories?post=200990"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/tags?post=200990"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}