{"id":44762,"date":"2024-12-01T17:04:03","date_gmt":"2024-12-01T09:04:03","guid":{"rendered":"https:\/\/fwq.ai\/blog\/44762\/"},"modified":"2024-12-01T17:04:03","modified_gmt":"2024-12-01T09:04:03","slug":"%e5%a6%82%e4%bd%95%e5%90%88%e5%b9%b6-count-group-by-%e5%92%8c-select-%e8%af%ad%e5%8f%a5%ef%bc%9f-2","status":"publish","type":"post","link":"https:\/\/fwq.ai\/blog\/44762\/","title":{"rendered":"\u5982\u4f55\u5408\u5e76 COUNT GROUP BY \u548c SELECT \u8bed\u53e5\uff1f"},"content":{"rendered":"

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

\u5982\u4f55\u5408\u5e76 COUNT GROUP BY \u548c SELECT \u8bed\u53e5\uff1f<\/h1>\n

\u4e00\u5206\u8015\u8018\uff0c\u4e00\u5206\u6536\u83b7\uff01\u65e2\u7136\u6253\u5f00\u4e86\u8fd9\u7bc7\u6587\u7ae0\uff0c\u5c31\u575a\u6301\u770b\u4e0b\u53bb\u5427\uff01\u6587\u4e2d\u5185\u5bb9\u5305\u542b\u7b49\u7b49\u77e5\u8bc6\u70b9…\u5e0c\u671b\u4f60\u80fd\u5728\u9605\u8bfb\u672c\u6587\u540e\uff0c\u80fd\u771f\u771f\u5b9e\u5b9e\u5b66\u5230\u77e5\u8bc6\u6216\u8005\u5e2e\u4f60\u89e3\u51b3\u5fc3\u4e2d\u7684\u7591\u60d1\uff0c\u4e5f\u6b22\u8fce\u5927\u4f6c\u6216\u8005\u65b0\u4eba\u670b\u53cb\u4eec\u591a\u7559\u8a00\u8bc4\u8bba\uff0c\u591a\u7ed9\u5efa\u8bae\uff01\u8c22\u8c22\uff01<\/p>\n

\"\u5982\u4f55\u5408\u5e76<\/p>\n

\u5408\u5e76 count group by \u548c select \u8bed\u53e5<\/strong><\/p>\n

\u5728\u5bf9\u540c\u4e00\u5f20\u8868\u540c\u65f6\u6267\u884c count group by \u548c select \u64cd\u4f5c\u65f6\uff0c\u53ef\u4ee5\u8003\u8651\u4ee5\u4e0b\u5408\u5e76\u8bed\u53e5\u7684\u65b9\u6cd5\uff1a<\/p>\n

\u5408\u5e76 select \u548c count \u8bed\u53e5<\/strong><\/p>\n

\u53ef\u4ee5\u4f7f\u7528 select \u5b50\u53e5\u540c\u65f6\u83b7\u53d6\u6570\u636e\u548c\u8ba1\u6570\uff1a<\/p>\n

select t1.a, t1.b, count(*) as count from test as t1 group by t1.a, t1.b<\/pre>\n
\u8fd9\u5c06\u4ea7\u751f\u4e00\u7ec4\u65b0\u7684\u8bb0\u5f55\uff0c\u5176\u4e2d\u5305\u542b\u539f\u59cb\u8868\u4e2d\u7684\u5217\u4ee5\u53ca\u7528\u4e8e\u5206\u7ec4\u7684\u5217\u7684\u8ba1\u6570\u3002<\/p>\n
\u5408\u5e76 left join<\/strong><\/p>\n
\u53e6\u4e00\u79cd\u65b9\u6cd5\u662f\u6267\u884c left join\uff0c\u5c06\u539f\u59cb\u8868\u4e0e\u5206\u7ec4\u8868\u8054\u7cfb\u8d77\u6765\uff1a<\/p>\n
select t1.a, t1.b, t2.count from test as t1\nleft join (\n    select a, b, count(*) as count\n    from test\n    group by a, b\n) as t2 on t1.a = t2.a and t1.b = t2.b<\/pre>\n
left join \u5c06\u786e\u4fdd\u6240\u6709\u539f\u59cb\u884c\u90fd\u5305\u542b\u5728\u5176\u7ed3\u679c\u96c6\u4e2d\uff0c\u5176\u4e2d\u6765\u81ea\u5206\u7ec4\u8868\u7684\u8ba1\u6570\u5c06\u9644\u52a0\u5230\u5177\u6709\u5339\u914d\u5217\u503c\u7684\u884c\u7684\u672b\u5c3e\u3002<\/p>\n
\u4ee5\u4e0a\u5c31\u662f\u672c\u6587\u7684\u5168\u90e8\u5185\u5bb9\u4e86\uff0c\u662f\u5426\u6709\u987a\u5229\u5e2e\u52a9\u4f60\u89e3\u51b3\u95ee\u9898\uff1f\u82e5\u662f\u80fd\u7ed9\u4f60\u5e26\u6765\u5b66\u4e60\u4e0a\u7684\u5e2e\u52a9\uff0c\u8bf7\u5927\u5bb6\u591a\u591a\u652f\u6301\u7c73\u4e91\uff01\u66f4\u591a\u5173\u4e8e\u6570\u636e\u5e93\u7684\u76f8\u5173\u77e5\u8bc6\uff0c\u4e5f\u53ef\u5173\u6ce8\u7c73\u4e91\u516c\u4f17\u53f7\u3002<\/p>\n
\n
\n <\/dt>\n<\/dl>\n","protected":false},"excerpt":{"rendered":"
\u5982\u4f55\u5408\u5e76 COUNT GROUP BY \u548c SELECT \u8bed\u53e5\uff1f \u4e00\u5206\u8015\u8018\uff0c\u4e00\u5206\u6536\u83b7\uff01\u65e2\u7136\u6253\u5f00\u4e86\u8fd9\u7bc7\u6587\u7ae0\uff0c\u5c31\u575a\u6301\u770b\u4e0b\u53bb\u5427\uff01\u6587\u4e2d\u5185\u5bb9\u5305\u542b\u7b49\u7b49\u77e5\u8bc6\u70b9…\u5e0c\u671b\u4f60\u80fd\u5728\u9605\u8bfb\u672c\u6587\u540e\uff0c\u80fd\u771f\u771f\u5b9e\u5b9e\u5b66\u5230\u77e5\u8bc6\u6216\u8005\u5e2e\u4f60\u89e3\u51b3\u5fc3\u4e2d\u7684\u7591\u60d1\uff0c\u4e5f\u6b22\u8fce\u5927\u4f6c\u6216\u8005\u65b0\u4eba\u670b\u53cb\u4eec\u591a\u7559\u8a00\u8bc4\u8bba\uff0c\u591a\u7ed9\u5efa\u8bae\uff01\u8c22\u8c22\uff01 \u5408\u5e76 count group by \u548c select \u8bed\u53e5 \u5728\u5bf9\u540c\u4e00\u5f20\u8868\u540c\u65f6\u6267\u884c count group by \u548c select \u64cd\u4f5c\u65f6\uff0c\u53ef\u4ee5\u8003\u8651\u4ee5\u4e0b\u5408\u5e76\u8bed\u53e5\u7684\u65b9\u6cd5\uff1a \u5408\u5e76 select \u548c count \u8bed\u53e5 \u53ef\u4ee5\u4f7f\u7528 select \u5b50\u53e5\u540c\u65f6\u83b7\u53d6\u6570\u636e\u548c\u8ba1\u6570\uff1a select t1.a, t1.b, count(*) as count from test as t1 group by t1.a, t1.b \u8fd9\u5c06\u4ea7\u751f\u4e00\u7ec4\u65b0\u7684\u8bb0\u5f55\uff0c\u5176\u4e2d\u5305\u542b\u539f\u59cb\u8868\u4e2d\u7684\u5217\u4ee5\u53ca\u7528\u4e8e\u5206\u7ec4\u7684\u5217\u7684\u8ba1\u6570\u3002 \u5408\u5e76 left join \u53e6\u4e00\u79cd\u65b9\u6cd5\u662f\u6267\u884c left join\uff0c\u5c06\u539f\u59cb\u8868\u4e0e\u5206\u7ec4\u8868\u8054\u7cfb\u8d77\u6765\uff1a select t1.a, t1.b, t2.count […]<\/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-44762","post","type-post","status-publish","format-standard","hentry","category-16"],"_links":{"self":[{"href":"https:\/\/fwq.ai\/blog\/wp-json\/wp\/v2\/posts\/44762","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=44762"}],"version-history":[{"count":0,"href":"https:\/\/fwq.ai\/blog\/wp-json\/wp\/v2\/posts\/44762\/revisions"}],"wp:attachment":[{"href":"https:\/\/fwq.ai\/blog\/wp-json\/wp\/v2\/media?parent=44762"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/fwq.ai\/blog\/wp-json\/wp\/v2\/categories?post=44762"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/fwq.ai\/blog\/wp-json\/wp\/v2\/tags?post=44762"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}