{"id":200749,"date":"2025-05-06T11:20:57","date_gmt":"2025-05-06T03:20:57","guid":{"rendered":"https:\/\/server.hk\/cnblog\/200749\/"},"modified":"2025-05-06T11:20:57","modified_gmt":"2025-05-06T03:20:57","slug":"%e5%a6%82%e4%bd%95%e4%bd%bf%e7%94%a8-sql-%e6%9f%a5%e8%af%a2%e5%85%b3%e8%81%94%e8%a1%a8%e5%b9%b6%e9%81%bf%e5%85%8d%e9%87%8d%e5%a4%8d%e6%95%b0%e6%8d%ae%ef%bc%9f","status":"publish","type":"post","link":"https:\/\/server.hk\/cnblog\/200749\/","title":{"rendered":"\u5982\u4f55\u4f7f\u7528 SQL \u67e5\u8be2\u5173\u8054\u8868\u5e76\u907f\u514d\u91cd\u590d\u6570\u636e\uff1f"},"content":{"rendered":"

<\/b> <\/p>\n

\u5982\u4f55\u4f7f\u7528 SQL \u67e5\u8be2\u5173\u8054\u8868\u5e76\u907f\u514d\u91cd\u590d\u6570\u636e\uff1f<\/h1>\n

\u5c0f\u4f19\u4f34\u4eec\u6709\u6ca1\u6709\u89c9\u5f97\u5b66\u4e60\u5f88\u6709\u610f\u601d\uff1f\u6709\u610f\u601d\u5c31\u5bf9\u4e86\uff01\u4eca\u5929\u5c31\u7ed9\u5927\u5bb6\u5e26\u6765\uff0c\u4ee5\u4e0b\u5185\u5bb9\u5c06\u4f1a\u6d89\u53ca\u5230\uff0c\u82e5\u662f\u5728\u5b66\u4e60\u4e2d\u5bf9\u5176\u4e2d\u90e8\u5206\u77e5\u8bc6\u70b9\u6709\u7591\u95ee\uff0c\u6216\u8bb8\u770b\u4e86\u672c\u6587\u5c31\u80fd\u5e2e\u5230\u4f60\uff01<\/p>\n

<\/p>\n

sql \u67e5\u8be2\u6c42\u6551<\/strong><\/p>\n

\u5728\u5904\u7406\u5173\u8054\u8868\u67e5\u8be2\u65f6\uff0c\u7ecf\u5e38\u4f1a\u9047\u5230\u91cd\u590d\u6570\u636e\u7684\u95ee\u9898\u3002\u672c\u6587\u5c06\u9488\u5bf9\u6b64\u95ee\u9898\u63d0\u4f9b\u89e3\u51b3\u65b9\u6848\uff0c\u901a\u8fc7 sql \u8bed\u53e5\u5b9e\u73b0\u65e0\u91cd\u590d\u67e5\u8be2\u7ed3\u679c\u3002<\/p>\n

\u5047\u8bbe\u6709\u4ee5\u4e0b\u4e24\u5f20\u8868\uff1a<\/p>\n

\u8868 a\uff1a\n\n| sid | name |\n| -------- | -------- |\n| 1 | \u5f20\u4e09 |\n| 2 | \u674e\u56db |\n\n\u8868 b\uff1a\n\n| sid | tracking_number |\n| -------- | -------- |\n| 1 | 12345 |\n| 1 | 67890 |\n| 2 | 34567 |<\/pre>\n
\u76ee\u6807\u662f\u57fa\u4e8e\u8868 a \u67e5\u8be2\uff0c\u6309\u7167 sid \u8fdb\u884c\u5173\u8054\uff0c\u4f46\u53ea\u4fdd\u7559\u552f\u4e00\u7684\u67e5\u8be2\u7ed3\u679c\u3002\u4e3a\u6b64\uff0c\u53ef\u4ee5\u91c7\u7528\u4ee5\u4e0b sql \u8bed\u53e5\uff1a<\/p>\n
select *\nfrom a\nleft join (\n  select sid, max(tracking_number) as tracking_number\n  from b\n  group by sid\n) b\non a.sid = b.sid<\/pre>\n
\u8be5\u8bed\u53e5\u5c06\u6839\u636e sid \u5bf9\u8868 b \u8fdb\u884c\u5206\u7ec4\uff0c\u5e76\u83b7\u53d6\u6bcf\u4e2a\u7ec4\u4e2d\u6700\u5927\u7684 tracking_number\uff0c\u7136\u540e\u4e0e\u8868 a \u5de6\u8fde\u63a5\u3002\u8fd9\u6837\uff0c\u6700\u7ec8\u67e5\u8be2\u7ed3\u679c\u53ea\u5305\u542b\u65e0\u91cd\u590d\u7684 sid \u8bb0\u5f55\u4ee5\u53ca\u5bf9\u5e94\u7684\u6700\u5927 tracking_number\u3002<\/p>\n
\u53e6\u5916\uff0c\u8fd8\u53ef\u4ee5\u6839\u636e\u5177\u4f53\u60c5\u51b5\u4f7f\u7528\u4ee5\u4e0b\u8bed\u53e5\uff1a<\/p>\n
SELECT\n    a.*,\n    b.tracking_number\nFROM a\nLEFT JOIN (\n    SELECT MAX(ID) AS id, sid\n    FROM b\n    GROUP BY sid\n) x ON a.sid = x.sid\nLEFT JOIN b ON x.id = b.id<\/pre>\n
\u6b64\u8bed\u53e5\u4f7f\u7528\u4e3b\u952e id \u8fdb\u884c\u6700\u5927\u503c\u805a\u5408\uff0c\u7136\u540e\u901a\u8fc7 x \u8868\u5173\u8054\u56de\u8868 b \u83b7\u53d6\u5176\u4ed6\u4fe1\u606f\u3002<\/p>\n
\u4eca\u5929\u5e26\u5927\u5bb6\u4e86\u89e3\u4e86\u7684\u76f8\u5173\u77e5\u8bc6\uff0c\u5e0c\u671b\u5bf9\u4f60\u6709\u6240\u5e2e\u52a9\uff1b\u5173\u4e8e\u6570\u636e\u5e93\u7684\u6280\u672f\u77e5\u8bc6\u6211\u4eec\u4f1a\u4e00\u70b9\u70b9\u6df1\u5165\u4ecb\u7ecd\uff0c\u6b22\u8fce\u5927\u5bb6\u5173\u6ce8\u4e3b\u673a\u5b9d\u8d1d\u516c\u4f17\u53f7\uff0c\u4e00\u8d77\u5b66\u4e60\u7f16\u7a0b~<\/p>\n
\n
\n <\/dt>\n<\/dl>\n","protected":false},"excerpt":{"rendered":"
\u5982\u4f55\u4f7f\u7528 SQL \u67e5\u8be2\u5173\u8054\u8868\u5e76\u907f...<\/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-200749","post","type-post","status-publish","format-standard","hentry","category-database"],"_links":{"self":[{"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/posts\/200749","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=200749"}],"version-history":[{"count":0,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/posts\/200749\/revisions"}],"wp:attachment":[{"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/media?parent=200749"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/categories?post=200749"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/tags?post=200749"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}