{"id":7131,"date":"2024-11-14T13:49:58","date_gmt":"2024-11-14T05:49:58","guid":{"rendered":"https:\/\/fwq.ai\/blog\/7131\/"},"modified":"2024-11-14T13:49:58","modified_gmt":"2024-11-14T05:49:58","slug":"%e5%a6%82%e4%bd%95%e4%bd%bf%e7%94%a8-sql-%e6%9f%a5%e8%af%a2%e5%ae%9e%e7%8e%b0%e5%9f%ba%e5%87%86%e8%a1%a8%e6%97%a0%e9%87%8d%e5%a4%8d%e7%bb%93%e6%9e%9c%e8%bf%9e%e6%8e%a5%ef%bc%9f","status":"publish","type":"post","link":"https:\/\/fwq.ai\/blog\/7131\/","title":{"rendered":"\u5982\u4f55\u4f7f\u7528 SQL \u67e5\u8be2\u5b9e\u73b0\u57fa\u51c6\u8868\u65e0\u91cd\u590d\u7ed3\u679c\u8fde\u63a5\uff1f"},"content":{"rendered":"<p><img decoding=\"async\" src=\"https:\/\/img.php.cn\/upload\/article\/001\/246\/273\/173046691770267.jpg\" class=\"aligncenter\" title=\"\u5982\u4f55\u4f7f\u7528 SQL \u67e5\u8be2\u5b9e\u73b0\u57fa\u51c6\u8868\u65e0\u91cd\u590d\u7ed3\u679c\u8fde\u63a5\uff1f\u63d2\u56fe\" alt=\"\u5982\u4f55\u4f7f\u7528 SQL \u67e5\u8be2\u5b9e\u73b0\u57fa\u51c6\u8868\u65e0\u91cd\u590d\u7ed3\u679c\u8fde\u63a5\uff1f\u63d2\u56fe\" \/><\/p>\n<p><strong>sql \u67e5\u8be2\uff1a\u6309\u57fa\u51c6\u8868\u6c42\u65e0\u91cd\u590d\u7ed3\u679c<\/strong><\/p>\n<p>\u6570\u636e\u5e93\u4e2d\u7ecf\u5e38\u9700\u8981\u5904\u7406\u591a\u8868\u8fde\u63a5\u67e5\u8be2\u7684\u95ee\u9898\u3002\u5f53\u60f3\u8981\u67e5\u8be2\u4ee5\u67d0\u5f20\u8868\u4e3a\u57fa\u51c6\uff0c\u5e76\u4e14\u907f\u514d\u51fa\u73b0\u91cd\u590d\u7ed3\u679c\u65f6\uff0c\u53ef\u4ee5\u4f7f\u7528\u9002\u5f53\u7684 sql \u8bed\u53e5\u3002<\/p>\n<p>\u8003\u8651\u4ee5\u4e0b\u573a\u666f\uff1a<\/p>\n<p>\u6211\u4eec\u6709\u4e24\u4e2a\u8868\uff1aa \u548c b\u3002a \u8868\u6709 sid\uff08\u5b66\u751f id\uff09\u548c name\uff08\u59d3\u540d\uff09\u5b57\u6bb5\uff0c\u800c b \u8868\u6709 sid \u548c tracking_number\uff08\u8ffd\u8e2a\u53f7\uff09\u5b57\u6bb5\u3002<\/p>\n<p>\u4e3a\u4e86\u67e5\u8be2\u4ee5 a \u8868\u4e3a\u57fa\u51c6\uff0c\u53ea\u4fdd\u7559\u6bcf\u4e2a\u5b66\u751f\u552f\u4e00\u7684\u7ed3\u679c\uff0c\u6211\u4eec\u53ef\u4ee5\u4f7f\u7528\u4ee5\u4e0b sql \u8bed\u53e5\uff1a<\/p>\n<pre>select *\nfrom a\nleft join (\n  select sid, max(tracking_number)\n  from b\n  group by sid\n) b\non a.sid = b.sid<\/pre>\n<p>  \u767b\u5f55\u540e\u590d\u5236   <\/p>\n<p>\u8fd9\u4e2a\u8bed\u53e5\u4f7f\u7528 left join\uff0c\u5c06 a \u8868\u4e0e\u4e00\u4e2a\u5b50\u67e5\u8be2\u8fde\u63a5\u8d77\u6765\u3002\u5b50\u67e5\u8be2\u7684\u529f\u80fd\u662f\u4e3a\u6bcf\u4e2a\u5b66\u751f\u627e\u5230\u6700\u65b0\u7684 tracking_number\u3002\u901a\u8fc7\u4f7f\u7528 max \u51fd\u6570\uff0c\u6211\u4eec\u53ef\u4ee5\u786e\u4fdd\u53ea\u6709\u6700\u65b0\u7684\u8ffd\u8e2a\u53f7\u88ab\u4fdd\u7559\u3002<\/p>\n<p>\u9700\u8981\u6ce8\u610f\u7684\u662f\uff0c\u6709\u4e9b\u6570\u636e\u5e93\u4e0d\u9700\u8981 max \u51fd\u6570\uff0c\u800c\u53ef\u4ee5\u76f4\u63a5\u4f7f\u7528 tracking_number \u5b57\u6bb5\u3002\u8bf7\u6839\u636e\u4f60\u7684\u6570\u636e\u5e93\u7248\u672c\u8fdb\u884c\u8c03\u6574\u3002<\/p>\n<p>\u5982\u679c\u9700\u8981\u4f7f\u7528\u51fd\u6570\uff0c\u5e76\u4e14\u60f3\u8981\u540c\u65f6\u4fdd\u7559\u5176\u4ed6\u4fe1\u606f\uff0c\u53ef\u4ee5\u4f7f\u7528\u4ee5\u4e0b\u8bed\u53e5\uff1a<\/p>\n<pre>SELECT\n    a.*,\n    b.tracking_number,\n    b.is_cancel \nFROM a\nLEFT JOIN (\n    SELECT MAX(id) 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<p>  \u767b\u5f55\u540e\u590d\u5236   <\/p>\n<p>\u8fd9\u4e2a\u8bed\u53e5\u9996\u5148\u4f7f\u7528 max \u51fd\u6570\u627e\u5230\u6bcf\u4e2a\u5b66\u751f\u7684\u6700\u65b0 id\uff0c\u7136\u540e\u901a\u8fc7\u8fde\u63a5 b \u8868\uff0c\u5c06\u5176\u4ed6\u4fe1\u606f\u5e26\u51fa\u6765\u3002<\/p>\n<p>\u4ee5\u4e0a\u5c31\u662f\u5982\u4f55\u4f7f\u7528 SQL \u67e5\u8be2\u5b9e\u73b0\u57fa\u51c6\u8868\u65e0\u91cd\u590d\u7ed3\u679c\u8fde\u63a5\uff1f\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":"<p>sql \u67e5\u8be2\uff1a\u6309\u57fa\u51c6\u8868\u6c42\u65e0\u91cd\u590d\u7ed3\u679c \u6570\u636e\u5e93\u4e2d\u7ecf\u5e38\u9700\u8981\u5904\u7406\u591a\u8868\u8fde\u63a5\u67e5\u8be2\u7684\u95ee\u9898\u3002\u5f53\u60f3\u8981\u67e5\u8be2\u4ee5\u67d0\u5f20\u8868\u4e3a\u57fa\u51c6\uff0c\u5e76\u4e14\u907f\u514d\u51fa\u73b0\u91cd\u590d\u7ed3\u679c\u65f6\uff0c\u53ef\u4ee5\u4f7f\u7528\u9002\u5f53\u7684 sql \u8bed\u53e5\u3002 \u8003\u8651\u4ee5\u4e0b\u573a\u666f\uff1a \u6211\u4eec\u6709\u4e24\u4e2a\u8868\uff1aa \u548c b\u3002a \u8868\u6709 sid\uff08\u5b66\u751f id\uff09\u548c name\uff08\u59d3\u540d\uff09\u5b57\u6bb5\uff0c\u800c b \u8868\u6709 sid \u548c tracking_number\uff08\u8ffd\u8e2a\u53f7\uff09\u5b57\u6bb5\u3002 \u4e3a\u4e86\u67e5\u8be2\u4ee5 a \u8868\u4e3a\u57fa\u51c6\uff0c\u53ea\u4fdd\u7559\u6bcf\u4e2a\u5b66\u751f\u552f\u4e00\u7684\u7ed3\u679c\uff0c\u6211\u4eec\u53ef\u4ee5\u4f7f\u7528\u4ee5\u4e0b sql \u8bed\u53e5\uff1a select * from a left join ( select sid, max(tracking_number) from b group by sid ) b on a.sid = b.sid \u767b\u5f55\u540e\u590d\u5236 \u8fd9\u4e2a\u8bed\u53e5\u4f7f\u7528 left join\uff0c\u5c06 a \u8868\u4e0e\u4e00\u4e2a\u5b50\u67e5\u8be2\u8fde\u63a5\u8d77\u6765\u3002\u5b50\u67e5\u8be2\u7684\u529f\u80fd\u662f\u4e3a\u6bcf\u4e2a\u5b66\u751f\u627e\u5230\u6700\u65b0\u7684 tracking_number\u3002\u901a\u8fc7\u4f7f\u7528 max \u51fd\u6570\uff0c\u6211\u4eec\u53ef\u4ee5\u786e\u4fdd\u53ea\u6709\u6700\u65b0\u7684\u8ffd\u8e2a\u53f7\u88ab\u4fdd\u7559\u3002 \u9700\u8981\u6ce8\u610f\u7684\u662f\uff0c\u6709\u4e9b\u6570\u636e\u5e93\u4e0d\u9700\u8981 max [&hellip;]<\/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-7131","post","type-post","status-publish","format-standard","hentry","category-16"],"_links":{"self":[{"href":"https:\/\/fwq.ai\/blog\/wp-json\/wp\/v2\/posts\/7131","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=7131"}],"version-history":[{"count":0,"href":"https:\/\/fwq.ai\/blog\/wp-json\/wp\/v2\/posts\/7131\/revisions"}],"wp:attachment":[{"href":"https:\/\/fwq.ai\/blog\/wp-json\/wp\/v2\/media?parent=7131"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/fwq.ai\/blog\/wp-json\/wp\/v2\/categories?post=7131"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/fwq.ai\/blog\/wp-json\/wp\/v2\/tags?post=7131"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}