{"id":201007,"date":"2025-05-06T10:26:37","date_gmt":"2025-05-06T02:26:37","guid":{"rendered":"https:\/\/server.hk\/cnblog\/201007\/"},"modified":"2025-05-06T10:26:37","modified_gmt":"2025-05-06T02:26:37","slug":"mysql%e5%85%b3%e8%81%94%e6%9f%a5%e8%af%a2%e4%b8%ad%ef%bc%8cp2-product_type-p1-product_type-%e5%92%8c%e5%88%86%e7%bb%84%e6%93%8d%e4%bd%9c%e7%9a%84%e4%bd%9c%e7%94%a8%e6%98%af%e4%bb%80%e4%b9%88","status":"publish","type":"post","link":"https:\/\/server.hk\/cnblog\/201007\/","title":{"rendered":"MySQL\u5173\u8054\u67e5\u8be2\u4e2d\uff0cp2.product_type = p1.product_type \u548c\u5206\u7ec4\u64cd\u4f5c\u7684\u4f5c\u7528\u662f\u4ec0\u4e48\uff1f"},"content":{"rendered":"<p><b><\/b> <\/p>\n<h1>MySQL\u5173\u8054\u67e5\u8be2\u4e2d\uff0cp2.product_type = p1.product_type \u548c\u5206\u7ec4\u64cd\u4f5c\u7684\u4f5c\u7528\u662f\u4ec0\u4e48\uff1f<\/h1>\n<\/p>\n<p><img decoding=\"async\" src=\"https:\/\/www.17golang.com\/uploads\/20241125\/173251048467440314816d8.jpg\" class=\"aligncenter\"><\/p>\n<p><strong>mysql\u5173\u8054\u67e5\u8be2\u4e2d\u7684\u56f0\u60d1\uff1ap2.product_type = p1.product_type<\/strong><\/p>\n<p>\u5728\u8fdb\u884cmysql\u5173\u8054\u67e5\u8be2\u65f6\uff0c\u4f60\u662f\u5426\u9047\u5230\u8fc7\u7c7b\u4f3c\u8fd9\u6837\u7684\u7591\u95ee\uff1a\u300c\u4e3a\u4f55\u4f7f\u7528\u4e86p2.product_type = p1.product_type\u6761\u4ef6\uff0c\u5e76\u4e14\u8fd8\u8981\u5206\u7ec4\uff0c\u5b83\u4eec\u7684\u76ee\u7684\u662f\u4ec0\u4e48\uff1f\u300d<\/p>\n<p>\u8981\u7406\u89e3\u8fd9\u4e00\u95ee\u9898\uff0c\u6211\u4eec\u9700\u8981\u9996\u5148\u4e86\u89e3\u522b\u540d\u3002 <strong>\u522b\u540d<\/strong>\u5141\u8bb8\u6211\u4eec\u4f7f\u7528\u4e0d\u540c\u7684\u540d\u79f0\u6765\u5f15\u7528\u540c\u4e00\u5f20\u8868\uff0c\u5728\u672c\u4f8b\u4e2d\uff0cp2\u662fproduct\u8868\u7684\u522b\u540d\u3002 <\/p>\n<p>p2.product_type = p1.product_type\u6761\u4ef6\u786e\u4fdd\u4e86p1\u8868\u4e2d\u7684\u4ea7\u54c1\u7c7b\u578b\u4e0ep2\u8868\u4e2d\u7684\u4ea7\u54c1\u7c7b\u578b\u76f8\u5339\u914d\u3002\u6362\u53e5\u8bdd\u8bf4\uff0c\u5b83\u8fc7\u6ee4\u6389\u4e86p2\u8868\u4e2d\u4e0d\u4e0ep1\u8868\u4e2d\u7684\u4ea7\u54c1\u7c7b\u578b\u76f8\u5339\u914d\u7684\u884c\u3002 <\/p>\n<p>\u81f3\u4e8e\u5206\u7ec4\uff0c\u5b83\u7528\u6765\u5c06\u5177\u6709\u76f8\u540cproduct_type\u503c\u7684\u884c\u5206\u7ec4\u5728\u4e00\u8d77\u3002\u901a\u8fc7\u5206\u7ec4\uff0c\u6211\u4eec\u53ef\u4ee5\u8ba1\u7b97\u6bcf\u4e2a\u4e0d\u540c\u4ea7\u54c1\u7684\u5e73\u5747\u503c\u3002 <\/p>\n<p>\u5982\u679c\u4e0d\u5bf9product_type\u5206\u7ec4\uff0c\u67e5\u8be2\u5c06\u9488\u5bf9\u6574\u4e2aproduct\u8868\u8ba1\u7b97\u5e73\u5747\u503c\u3002\u7136\u800c\uff0c\u901a\u8fc7\u5206\u7ec4\uff0c\u6211\u4eec\u80fd\u591f\u9488\u5bf9\u4e0d\u540c\u7684\u4ea7\u54c1\u7c7b\u578b\u8ba1\u7b97\u5e73\u5747\u503c\u3002 <\/p>\n<p>\u4e3a\u4e86\u8fdb\u4e00\u6b65\u8bf4\u660e\uff0c\u8ba9\u6211\u4eec\u8003\u8651\u4ee5\u4e0b\u793a\u4f8b\u67e5\u8be2\uff1a<\/p>\n<pre>SELECT product_type, AVG(price)\nFROM product AS p1\nJOIN product AS p2 ON p2.product_type = p1.product_type\nGROUP BY product_type;<\/pre>\n<p>\u4e0d\u4f7f\u7528\u5206\u7ec4\u65f6\uff0c\u67e5\u8be2\u7ed3\u679c\u5982\u4e0b\uff1a<\/p>\n<table>\n<thead>\n<tr>\n<th>product_type<\/th>\n<th>avg(price)<\/th>\n<\/tr>\n<\/thead>\n<tbody>\n<tr>\n<td>\u6240\u6709\u4ea7\u54c1\u7c7b\u578b<\/td>\n<td>100<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<p>\u4f7f\u7528\u5206\u7ec4\u65f6\uff0c\u67e5\u8be2\u7ed3\u679c\u5982\u4e0b\uff1a <\/p>\n<table>\n<thead>\n<tr>\n<th>product_type<\/th>\n<th>avg(price)<\/th>\n<\/tr>\n<\/thead>\n<tbody>\n<tr>\n<td>\u7c7b\u578b a<\/td>\n<td>50<\/td>\n<\/tr>\n<tr>\n<td>\u7c7b\u578b b<\/td>\n<td>150<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<p>\u901a\u8fc7\u5206\u7ec4\uff0c\u6211\u4eec\u80fd\u591f\u4e86\u89e3\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\uff0cp2.product_type = p1.product_type \u548c\u5206\u7ec4\u64cd\u4f5c\u7684\u4f5c\u7528\u662f\u4ec0\u4e48\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\uff0cp2.pr&#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-201007","post","type-post","status-publish","format-standard","hentry","category-database"],"_links":{"self":[{"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/posts\/201007","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=201007"}],"version-history":[{"count":0,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/posts\/201007\/revisions"}],"wp:attachment":[{"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/media?parent=201007"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/categories?post=201007"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/tags?post=201007"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}