{"id":201003,"date":"2025-05-06T09:32:17","date_gmt":"2025-05-06T01:32:17","guid":{"rendered":"https:\/\/server.hk\/cnblog\/201003\/"},"modified":"2025-05-06T09:32:17","modified_gmt":"2025-05-06T01:32:17","slug":"mysql-%e5%85%b3%e8%81%94%e6%9f%a5%e8%af%a2%e4%b8%ad%ef%bc%8c%e5%88%86%e7%bb%84%e5%92%8c%e5%88%ab%e5%90%8d%e6%9c%89%e4%bb%80%e4%b9%88%e4%bd%9c%e7%94%a8%ef%bc%9f","status":"publish","type":"post","link":"https:\/\/server.hk\/cnblog\/201003\/","title":{"rendered":"MySQL \u5173\u8054\u67e5\u8be2\u4e2d\uff0c\u5206\u7ec4\u548c\u522b\u540d\u6709\u4ec0\u4e48\u4f5c\u7528\uff1f"},"content":{"rendered":"<p><b><\/b> <\/p>\n<h1>MySQL \u5173\u8054\u67e5\u8be2\u4e2d\uff0c\u5206\u7ec4\u548c\u522b\u540d\u6709\u4ec0\u4e48\u4f5c\u7528\uff1f<\/h1>\n<p>\u6765\u5230\u4e3b\u673a\u5b9d\u8d1d\u7684\u5927\u5bb6\uff0c\u76f8\u4fe1\u90fd\u662f\u7f16\u7a0b\u5b66\u4e60\u7231\u597d\u8005\uff0c\u5e0c\u671b\u5728\u8fd9\u91cc\u5b66\u4e60\u6570\u636e\u5e93\u76f8\u5173\u7f16\u7a0b\u77e5\u8bc6\u3002\u4e0b\u9762\u672c\u7bc7\u6587\u7ae0\u5c31\u6765\u5e26\u5927\u5bb6\u804a\u804a\u300aMySQL \u5173\u8054\u67e5\u8be2\u4e2d\uff0c\u5206\u7ec4\u548c\u522b\u540d\u6709\u4ec0\u4e48\u4f5c\u7528\uff1f\u300b\uff0c\u4ecb\u7ecd\u4e00\u4e0b\uff0c\u5e0c\u671b\u5bf9\u5927\u5bb6\u7684\u77e5\u8bc6\u79ef\u7d2f\u6709\u6240\u5e2e\u52a9\uff0c\u52a9\u529b\u5b9e\u6218\u5f00\u53d1\uff01<\/p>\n<p><img decoding=\"async\" src=\"https:\/\/www.17golang.com\/uploads\/20241125\/17324982526743d34cec98e.jpg\" class=\"aligncenter\"><\/p>\n<p><strong>\u7406\u89e3 mysql \u5173\u8054\u67e5\u8be2\u4e2d\u7684\u5206\u7ec4\u548c\u522b\u540d<\/strong><\/p>\n<p>\u5728 mysql \u5173\u8054\u67e5\u8be2\u4e2d\uff0c\u4f7f\u7528\u5b50\u67e5\u8be2\u6216\u8fde\u63a5\u591a\u4e2a\u8868\u65f6\u7ecf\u5e38\u9700\u8981\u4f7f\u7528\u5173\u8054\u548c\u5206\u7ec4\u3002\u4e00\u4e2a\u5e38\u89c1\u7684\u95ee\u9898\u662f\u4e3a\u4ec0\u4e48\u9700\u8981\u4f7f\u7528 join \u8bed\u53e5\u4e2d\u7684 on \u6761\u4ef6\u548c\u5206\u7ec4\u6761\u4ef6\u3002<\/p>\n<p><strong>on \u6761\u4ef6\u4e2d\u7684\u522b\u540d\uff1ap2.product_type = p1.product_type<\/strong><\/p>\n<p>p2 \u662f\u4e00\u4e2a\u522b\u540d\uff0c\u5b83\u4ee3\u8868 from product as p2 \u4e2d\u7684 product \u8868\u3002\u4f7f\u7528\u522b\u540d\u662f\u4e3a\u4e86\u7b80\u5316\u67e5\u8be2\uff0c\u907f\u514d\u4f7f\u7528\u957f\u8868\u540d\u3002<\/p>\n<p><strong>\u5206\u7ec4\u6761\u4ef6\uff1agroup by p2.product_type<\/strong><\/p>\n<p>\u5206\u7ec4\u6761\u4ef6\u7528\u4e8e\u5c06\u67e5\u8be2\u7ed3\u679c\u6309 p2.product_type \u5217\u7684\u503c\u8fdb\u884c\u5206\u7ec4\u3002\u5206\u7ec4\u7684\u76ee\u7684\u662f\u8ba1\u7b97\u540c\u4e00 product_type \u7684\u5e73\u5747\u503c\uff0c\u800c\u4e0d\u662f\u8ba1\u7b97\u6574\u4e2a\u8868\u7684\u5e73\u5747\u503c\u3002<\/p>\n<p><strong>\u5982\u679c\u4e0d\u5206\u7ec4<\/strong><\/p>\n<p>\u5982\u679c\u4e0d\u5206\u7ec4\uff0c\u67e5\u8be2\u5c06\u8ba1\u7b97\u6240\u6709\u884c\u7684\u5e73\u5747\u503c\uff0c\u800c\u4e0d\u4ec5\u4ec5\u662f\u4e0d\u540c product_type \u7684\u5e73\u5747\u503c\u3002\u4f8b\u5982\uff0c\u4ee5\u4e0b\u67e5\u8be2\u5c06\u8ba1\u7b97\u6240\u6709\u4ea7\u54c1\u7684\u5e73\u5747\u4ef7\u683c\uff1a<\/p>\n<pre>select avg(price) from product;<\/pre>\n<p><strong>\u5206\u7ec4\u540e<\/strong><\/p>\n<p>\u5206\u7ec4\u540e\uff0c\u67e5\u8be2\u5c06\u5206\u522b\u8ba1\u7b97\u6bcf\u79cd product_type \u7684\u5e73\u5747\u4ef7\u683c\uff1a<\/p>\n<pre>SELECT p2.product_type, AVG(p2.price)\nFROM product AS p2\nGROUP BY p2.product_type;<\/pre>\n<p>\u901a\u8fc7\u5206\u7ec4\uff0c\u6211\u4eec\u53ef\u4ee5\u83b7\u5f97\u66f4\u5177\u4f53\u7684\u4fe1\u606f\uff0c\u6bd4\u5982\u4e0d\u540c\u4ea7\u54c1\u7c7b\u578b\u7684\u5e73\u5747\u4ef7\u683c\u3002<\/p>\n<p>\u7406\u8bba\u8981\u638c\u63e1\uff0c\u5b9e\u64cd\u4e0d\u80fd\u843d\uff01\u4ee5\u4e0a\u5173\u4e8e\u300aMySQL \u5173\u8054\u67e5\u8be2\u4e2d\uff0c\u5206\u7ec4\u548c\u522b\u540d\u6709\u4ec0\u4e48\u4f5c\u7528\uff1f\u300b\u7684\u8be6\u7ec6\u4ecb\u7ecd\uff0c\u5927\u5bb6\u90fd\u638c\u63e1\u4e86\u5427\uff01\u5982\u679c\u60f3\u8981\u7ee7\u7eed\u63d0\u5347\u81ea\u5df1\u7684\u80fd\u529b\uff0c\u90a3\u4e48\u5c31\u6765\u5173\u6ce8\u4e3b\u673a\u5b9d\u8d1d\u516c\u4f17\u53f7\u5427\uff01<\/p>\n<dl>\n<dt>\n <\/dt>\n<\/dl>\n","protected":false},"excerpt":{"rendered":"<p>MySQL \u5173\u8054\u67e5\u8be2\u4e2d\uff0c\u5206\u7ec4\u548c\u522b&#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-201003","post","type-post","status-publish","format-standard","hentry","category-database"],"_links":{"self":[{"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/posts\/201003","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=201003"}],"version-history":[{"count":0,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/posts\/201003\/revisions"}],"wp:attachment":[{"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/media?parent=201003"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/categories?post=201003"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/tags?post=201003"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}