{"id":181266,"date":"2024-11-09T15:37:17","date_gmt":"2024-11-09T07:37:17","guid":{"rendered":"https:\/\/server.hk\/cnblog\/181266\/"},"modified":"2024-11-09T15:37:18","modified_gmt":"2024-11-09T07:37:18","slug":"%e6%b7%b1%e5%85%a5%e7%90%86%e8%a7%a3sql%e6%95%b8%e6%93%9a%e5%ba%ab%e5%ad%90%e6%9f%a5%e8%a9%a2%ef%bc%88sql%e6%95%b8%e6%93%9a%e5%ba%ab%e5%ad%90%e6%9f%a5%e8%a9%a2%ef%bc%89","status":"publish","type":"post","link":"https:\/\/server.hk\/cnblog\/181266\/","title":{"rendered":"\u6df1\u5165\u7406\u89e3SQL\u6578\u64da\u5eab\u5b50\u67e5\u8a62\uff08sql\u6578\u64da\u5eab\u5b50\u67e5\u8a62\uff09"},"content":{"rendered":"<h1 id=\"%e6%b7%b1%e5%85%a5%e7%90%86%e8%a7%a3sql%e6%95%b8%e6%93%9a%e5%ba%ab%e5%ad%90%e6%9f%a5%e8%a9%a2-polLPGPAyD\">\u6df1\u5165\u7406\u89e3SQL\u6578\u64da\u5eab\u5b50\u67e5\u8a62<\/h1>\n<p>\u5728\u6578\u64da\u5eab\u7ba1\u7406\u7cfb\u7d71\u4e2d\uff0cSQL\uff08\u7d50\u69cb\u5316\u67e5\u8a62\u8a9e\u8a00\uff09\u662f\u4e00\u7a2e\u7528\u65bc\u67e5\u8a62\u548c\u64cd\u4f5c\u6578\u64da\u7684\u6a19\u6e96\u8a9e\u8a00\u3002\u5b50\u67e5\u8a62\u662fSQL\u4e2d\u4e00\u500b\u91cd\u8981\u7684\u6982\u5ff5\uff0c\u5b83\u5141\u8a31\u7528\u6236\u5728\u4e00\u500b\u67e5\u8a62\u4e2d\u5d4c\u5957\u53e6\u4e00\u500b\u67e5\u8a62\u3002\u9019\u7a2e\u6280\u8853\u4e0d\u50c5\u63d0\u9ad8\u4e86\u67e5\u8a62\u7684\u9748\u6d3b\u6027\uff0c\u9084\u80fd\u4f7f\u8907\u96dc\u7684\u6578\u64da\u6aa2\u7d22\u8b8a\u5f97\u66f4\u52a0\u7c21\u55ae\u548c\u9ad8\u6548\u3002<\/p>\n<h2 id=\"%e4%bb%80%e9%ba%bc%e6%98%af%e5%ad%90%e6%9f%a5%e8%a9%a2%ef%bc%9f-polLPGPAyD\">\u4ec0\u9ebc\u662f\u5b50\u67e5\u8a62\uff1f<\/h2>\n<p>\u5b50\u67e5\u8a62\u662f\u6307\u5728\u4e00\u500bSQL\u67e5\u8a62\u4e2d\u5d4c\u5957\u7684\u53e6\u4e00\u500b\u67e5\u8a62\u3002\u5b50\u67e5\u8a62\u53ef\u4ee5\u8fd4\u56de\u55ae\u500b\u503c\u3001\u884c\u6216\u591a\u884c\u6578\u64da\uff0c\u4e26\u4e14\u53ef\u4ee5\u7528\u65bc\u591a\u7a2e\u60c5\u6cc1\uff0c\u4f8b\u5982\u5728WHERE\u5b50\u53e5\u3001FROM\u5b50\u53e5\u6216SELECT\u5b50\u53e5\u4e2d\u4f7f\u7528\u3002\u5b50\u67e5\u8a62\u901a\u5e38\u7528\u62ec\u865f\u62ec\u8d77\u4f86\uff0c\u4ee5\u4fbf\u8207\u5916\u90e8\u67e5\u8a62\u5340\u5206\u958b\u4f86\u3002<\/p>\n<h2 id=\"%e5%ad%90%e6%9f%a5%e8%a9%a2%e7%9a%84%e9%a1%9e%e5%9e%8b-polLPGPAyD\">\u5b50\u67e5\u8a62\u7684\u985e\u578b<\/h2>\n<p>\u5b50\u67e5\u8a62\u4e3b\u8981\u6709\u4ee5\u4e0b\u5e7e\u7a2e\u985e\u578b\uff1a<\/p>\n<ul>\n<li><strong>\u55ae\u884c\u5b50\u67e5\u8a62\uff1a<\/strong>\u8fd4\u56de\u55ae\u500b\u503c\u7684\u5b50\u67e5\u8a62\uff0c\u901a\u5e38\u7528\u65bc\u6bd4\u8f03\u904b\u7b97\u7b26\u4e2d\u3002<\/li>\n<li><strong>\u591a\u884c\u5b50\u67e5\u8a62\uff1a<\/strong>\u8fd4\u56de\u591a\u884c\u6578\u64da\u7684\u5b50\u67e5\u8a62\uff0c\u901a\u5e38\u7528\u65bcIN\u6216EXISTS\u904b\u7b97\u7b26\u4e2d\u3002<\/li>\n<li><strong>\u76f8\u95dc\u5b50\u67e5\u8a62\uff1a<\/strong>\u9019\u7a2e\u5b50\u67e5\u8a62\u4f9d\u8cf4\u65bc\u5916\u90e8\u67e5\u8a62\u7684\u503c\uff0c\u901a\u5e38\u5728WHERE\u5b50\u53e5\u4e2d\u4f7f\u7528\u3002<\/li>\n<li><strong>\u975e\u76f8\u95dc\u5b50\u67e5\u8a62\uff1a<\/strong>\u9019\u7a2e\u5b50\u67e5\u8a62\u4e0d\u4f9d\u8cf4\u65bc\u5916\u90e8\u67e5\u8a62\u7684\u503c\uff0c\u53ef\u4ee5\u7368\u7acb\u57f7\u884c\u3002<\/li>\n<\/ul>\n<h2 id=\"%e5%ad%90%e6%9f%a5%e8%a9%a2%e7%9a%84%e4%bd%bf%e7%94%a8%e7%a4%ba%e4%be%8b-polLPGPAyD\">\u5b50\u67e5\u8a62\u7684\u4f7f\u7528\u793a\u4f8b<\/h2>\n<p>\u4ee5\u4e0b\u662f\u4e00\u4e9b\u4f7f\u7528\u5b50\u67e5\u8a62\u7684\u793a\u4f8b\uff1a<\/p>\n<h3 id=\"1-%e5%96%ae%e8%a1%8c%e5%ad%90%e6%9f%a5%e8%a9%a2-polLPGPAyD\">1. \u55ae\u884c\u5b50\u67e5\u8a62<\/h3>\n<pre><code>SELECT name \nFROM employees \nWHERE salary = (SELECT MAX(salary) FROM employees);<\/code><\/pre>\n<p>\u5728\u9019\u500b\u4f8b\u5b50\u4e2d\uff0c\u6211\u5011\u67e5\u8a62\u4e86\u85aa\u6c34\u6700\u9ad8\u7684\u54e1\u5de5\u7684\u59d3\u540d\u3002\u5167\u90e8\u67e5\u8a62\u8fd4\u56de\u6700\u9ad8\u85aa\u6c34\u7684\u503c\uff0c\u5916\u90e8\u67e5\u8a62\u5247\u6839\u64da\u9019\u500b\u503c\u6aa2\u7d22\u76f8\u61c9\u7684\u54e1\u5de5\u59d3\u540d\u3002<\/p>\n<h3 id=\"2-%e5%a4%9a%e8%a1%8c%e5%ad%90%e6%9f%a5%e8%a9%a2-polLPGPAyD\">2. \u591a\u884c\u5b50\u67e5\u8a62<\/h3>\n<pre><code>SELECT name \nFROM employees \nWHERE department_id IN (SELECT id FROM departments WHERE location = 'Hong Kong');<\/code><\/pre>\n<p>\u9019\u500b\u67e5\u8a62\u8fd4\u56de\u6240\u6709\u4f4d\u65bc\u9999\u6e2f\u7684\u90e8\u9580\u4e2d\u7684\u54e1\u5de5\u59d3\u540d\u3002\u5167\u90e8\u67e5\u8a62\u8fd4\u56de\u6240\u6709\u4f4d\u65bc\u9999\u6e2f\u7684\u90e8\u9580ID\uff0c\u5916\u90e8\u67e5\u8a62\u5247\u6839\u64da\u9019\u4e9bID\u6aa2\u7d22\u54e1\u5de5\u59d3\u540d\u3002<\/p>\n<h3 id=\"3-%e7%9b%b8%e9%97%9c%e5%ad%90%e6%9f%a5%e8%a9%a2-polLPGPAyD\">3. \u76f8\u95dc\u5b50\u67e5\u8a62<\/h3>\n<pre><code>SELECT e1.name \nFROM employees e1 \nWHERE e1.salary &gt; (SELECT AVG(salary) FROM employees e2 WHERE e1.department_id = e2.department_id);<\/code><\/pre>\n<p>\u5728\u9019\u500b\u4f8b\u5b50\u4e2d\uff0c\u6211\u5011\u67e5\u8a62\u4e86\u6240\u6709\u85aa\u6c34\u9ad8\u65bc\u5176\u6240\u5728\u90e8\u9580\u5e73\u5747\u85aa\u6c34\u7684\u54e1\u5de5\u59d3\u540d\u3002\u5167\u90e8\u67e5\u8a62\u6839\u64da\u5916\u90e8\u67e5\u8a62\u7684\u90e8\u9580ID\u8a08\u7b97\u5e73\u5747\u85aa\u6c34\u3002<\/p>\n<h2 id=\"%e5%ad%90%e6%9f%a5%e8%a9%a2%e7%9a%84%e5%84%aa%e7%bc%ba%e9%bb%9e-polLPGPAyD\">\u5b50\u67e5\u8a62\u7684\u512a\u7f3a\u9ede<\/h2>\n<p>\u4f7f\u7528\u5b50\u67e5\u8a62\u6709\u5176\u512a\u9ede\u548c\u7f3a\u9ede\uff1a<\/p>\n<ul>\n<li><strong>\u512a\u9ede\uff1a<\/strong>\n<ul>\n<li>\u63d0\u9ad8\u67e5\u8a62\u7684\u9748\u6d3b\u6027\uff0c\u80fd\u5920\u8655\u7406\u8907\u96dc\u7684\u6578\u64da\u6aa2\u7d22\u9700\u6c42\u3002<\/li>\n<li>\u4f7f\u67e5\u8a62\u7d50\u69cb\u66f4\u52a0\u6e05\u6670\uff0c\u6613\u65bc\u7406\u89e3\u3002<\/li>\n<\/ul>\n<\/li>\n<li><strong>\u7f3a\u9ede\uff1a<\/strong>\n<ul>\n<li>\u6027\u80fd\u554f\u984c\uff1a\u67d0\u4e9b\u60c5\u6cc1\u4e0b\uff0c\u5b50\u67e5\u8a62\u53ef\u80fd\u6703\u5c0e\u81f4\u6027\u80fd\u4e0b\u964d\uff0c\u7279\u5225\u662f\u7576\u5167\u90e8\u67e5\u8a62\u8fd4\u56de\u5927\u91cf\u6578\u64da\u6642\u3002<\/li>\n<li>\u53ef\u8b80\u6027\uff1a\u904e\u591a\u7684\u5d4c\u5957\u67e5\u8a62\u53ef\u80fd\u6703\u4f7fSQL\u8a9e\u53e5\u8b8a\u5f97\u96e3\u4ee5\u95b1\u8b80\u548c\u7dad\u8b77\u3002<\/li>\n<\/ul>\n<\/li>\n<\/ul>\n<h2 id=\"%e7%b8%bd%e7%b5%90-polLPGPAyD\">\u7e3d\u7d50<\/h2>\n<p>\u5b50\u67e5\u8a62\u662fSQL\u4e2d\u4e00\u500b\u5f37\u5927\u7684\u5de5\u5177\uff0c\u80fd\u5920\u5e6b\u52a9\u7528\u6236\u5728\u8907\u96dc\u7684\u6578\u64da\u6aa2\u7d22\u4e2d\u63d0\u9ad8\u9748\u6d3b\u6027\u548c\u6548\u7387\u3002\u901a\u904e\u7406\u89e3\u4e0d\u540c\u985e\u578b\u7684\u5b50\u67e5\u8a62\u53ca\u5176\u4f7f\u7528\u5834\u666f\uff0c\u958b\u767c\u8005\u53ef\u4ee5\u66f4\u6709\u6548\u5730\u8a2d\u8a08\u548c\u512a\u5316\u6578\u64da\u5eab\u67e5\u8a62\u3002\u5c0d\u65bc\u9700\u8981\u9ad8\u6548\u6578\u64da\u8655\u7406\u7684\u61c9\u7528\uff0c\u9078\u64c7\u5408\u9069\u7684\u6578\u64da\u5eab\u89e3\u6c7a\u65b9\u6848\u81f3\u95dc\u91cd\u8981\u3002\u82e5\u60a8\u5c0d\u65bc <a href=\"https:\/\/server.hk\">\u9999\u6e2fVPS<\/a> \u6216\u5176\u4ed6 <a href=\"https:\/\/server.hk\">\u4f3a\u670d\u5668<\/a> \u89e3\u6c7a\u65b9\u6848\u611f\u8208\u8da3\uff0c\u8acb\u8a2a\u554f\u6211\u5011\u7684\u7db2\u7ad9\u4ee5\u7372\u53d6\u66f4\u591a\u4fe1\u606f\u3002<\/p>\n","protected":false},"excerpt":{"rendered":"<p>\u6df1\u5165\u7406\u89e3SQL\u6578\u64da\u5eab\u5b50\u67e5\u8a62\uff0c\u638c\u63e1\u5176\u7528\u6cd5\u3001\u512a\u52e2\u53ca\u6700\u4f73\u5be6\u8e10\uff0c\u63d0\u5347\u6578\u64da\u67e5\u8a62\u6548\u7387\u8207\u9748\u6d3b\u6027\u3002<\/p>\n","protected":false},"author":0,"featured_media":0,"comment_status":"closed","ping_status":"","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[101],"tags":[],"class_list":["post-181266","post","type-post","status-publish","format-standard","hentry","category-database"],"_links":{"self":[{"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/posts\/181266","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"}],"replies":[{"embeddable":true,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/comments?post=181266"}],"version-history":[{"count":1,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/posts\/181266\/revisions"}],"predecessor-version":[{"id":181267,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/posts\/181266\/revisions\/181267"}],"wp:attachment":[{"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/media?parent=181266"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/categories?post=181266"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/tags?post=181266"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}