{"id":168441,"date":"2024-11-06T12:24:26","date_gmt":"2024-11-06T04:24:26","guid":{"rendered":"https:\/\/server.hk\/cnblog\/168441\/"},"modified":"2024-11-06T12:24:27","modified_gmt":"2024-11-06T04:24:27","slug":"sql-%e8%aa%9e%e5%8f%a5%e6%9f%a5%e8%a9%a2%e5%85%a9%e5%80%8b%e5%ad%97%e6%ae%b5%e7%9a%84%e6%96%b9%e6%b3%95-%e6%95%b8%e6%93%9a%e5%ba%ab%e4%b8%ad%e5%90%8c%e6%99%82%e6%9f%a5%e8%a9%a2%e5%85%a9%e5%80%8b","status":"publish","type":"post","link":"https:\/\/server.hk\/cnblog\/168441\/","title":{"rendered":"SQL \u8a9e\u53e5\u67e5\u8a62\u5169\u500b\u5b57\u6bb5\u7684\u65b9\u6cd5 (\u6578\u64da\u5eab\u4e2d\u540c\u6642\u67e5\u8a62\u5169\u500b\u5b57\u6bb5\u8a9e\u6cd5)"},"content":{"rendered":"<h1 id=\"sql-%e8%aa%9e%e5%8f%a5%e6%9f%a5%e8%a9%a2%e5%85%a9%e5%80%8b%e5%ad%97%e6%ae%b5%e7%9a%84%e6%96%b9%e6%b3%95-%e6%95%b8%e6%93%9a%e5%ba%ab%e4%b8%ad%e5%90%8c%e6%99%82%e6%9f%a5%e8%a9%a2%e5%85%a9%e5%80%8b-MyGBlPiHaA\">SQL \u8a9e\u53e5\u67e5\u8a62\u5169\u500b\u5b57\u6bb5\u7684\u65b9\u6cd5 (\u6578\u64da\u5eab\u4e2d\u540c\u6642\u67e5\u8a62\u5169\u500b\u5b57\u6bb5\u8a9e\u6cd5)<\/h1>\n<p>\u5728\u6578\u64da\u5eab\u7ba1\u7406\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\u7576\u6211\u5011\u9700\u8981\u5f9e\u6578\u64da\u5eab\u4e2d\u63d0\u53d6\u7279\u5b9a\u7684\u4fe1\u606f\u6642\uff0c\u7d93\u5e38\u6703\u9700\u8981\u67e5\u8a62\u591a\u500b\u5b57\u6bb5\u3002\u672c\u6587\u5c07\u63a2\u8a0e\u5982\u4f55\u4f7f\u7528 SQL \u8a9e\u53e5\u540c\u6642\u67e5\u8a62\u5169\u500b\u5b57\u6bb5\uff0c\u4e26\u63d0\u4f9b\u76f8\u95dc\u7684\u793a\u4f8b\u548c\u8a9e\u6cd5\u8aaa\u660e\u3002<\/p>\n<h2 id=\"%e5%9f%ba%e6%9c%ac%e7%9a%84-sql-%e6%9f%a5%e8%a9%a2%e8%aa%9e%e6%b3%95-MyGBlPiHaA\">\u57fa\u672c\u7684 SQL \u67e5\u8a62\u8a9e\u6cd5<\/h2>\n<p>\u5728 SQL \u4e2d\uff0c\u67e5\u8a62\u6578\u64da\u7684\u57fa\u672c\u8a9e\u6cd5\u70ba\uff1a<\/p>\n<pre><code>SELECT \u6b04\u4f4d1, \u6b04\u4f4d2 FROM \u8868\u683c\u540d\u7a31 WHERE \u689d\u4ef6;<\/code><\/pre>\n<p>\u9019\u88e1\u7684 <code>SELECT<\/code> \u662f\u7528\u4f86\u6307\u5b9a\u8981\u67e5\u8a62\u7684\u5b57\u6bb5\uff0c<code>FROM<\/code> \u7528\u4f86\u6307\u5b9a\u6578\u64da\u4f86\u6e90\u7684\u8868\u683c\uff0c<code>WHERE<\/code> \u5247\u662f\u7528\u4f86\u8a2d\u7f6e\u67e5\u8a62\u7684\u689d\u4ef6\u3002<\/p>\n<h2 id=\"%e6%9f%a5%e8%a9%a2%e5%85%a9%e5%80%8b%e5%ad%97%e6%ae%b5%e7%9a%84%e7%a4%ba%e4%be%8b-MyGBlPiHaA\">\u67e5\u8a62\u5169\u500b\u5b57\u6bb5\u7684\u793a\u4f8b<\/h2>\n<p>\u5047\u8a2d\u6211\u5011\u6709\u4e00\u500b\u540d\u70ba <code>\u54e1\u5de5<\/code> \u7684\u8868\u683c\uff0c\u8a72\u8868\u683c\u5305\u542b\u4ee5\u4e0b\u5b57\u6bb5\uff1a<\/p>\n<ul>\n<li><code>\u54e1\u5de5ID<\/code><\/li>\n<li><code>\u59d3\u540d<\/code><\/li>\n<li><code>\u90e8\u9580<\/code><\/li>\n<li><code>\u85aa\u8cc7<\/code><\/li>\n<\/ul>\n<p>\u5982\u679c\u6211\u5011\u60f3\u8981\u67e5\u8a62\u6240\u6709\u54e1\u5de5\u7684\u59d3\u540d\u548c\u90e8\u9580\uff0c\u53ef\u4ee5\u4f7f\u7528\u4ee5\u4e0b SQL \u8a9e\u53e5\uff1a<\/p>\n<pre><code>SELECT \u59d3\u540d, \u90e8\u9580 FROM \u54e1\u5de5;<\/code><\/pre>\n<p>\u9019\u689d\u8a9e\u53e5\u5c07\u8fd4\u56de\u6240\u6709\u54e1\u5de5\u7684\u59d3\u540d\u548c\u4ed6\u5011\u6240\u5c6c\u7684\u90e8\u9580\u3002<\/p>\n<h2 id=\"%e4%bd%bf%e7%94%a8%e6%a2%9d%e4%bb%b6%e6%9f%a5%e8%a9%a2%e5%85%a9%e5%80%8b%e5%ad%97%e6%ae%b5-MyGBlPiHaA\">\u4f7f\u7528\u689d\u4ef6\u67e5\u8a62\u5169\u500b\u5b57\u6bb5<\/h2>\n<p>\u5728\u5be6\u969b\u61c9\u7528\u4e2d\uff0c\u6211\u5011\u7d93\u5e38\u9700\u8981\u6839\u64da\u7279\u5b9a\u689d\u4ef6\u4f86\u7be9\u9078\u6578\u64da\u3002\u4f8b\u5982\uff0c\u5982\u679c\u6211\u5011\u53ea\u60f3\u67e5\u8a62\u85aa\u8cc7\u9ad8\u65bc 50000 \u7684\u54e1\u5de5\u7684\u59d3\u540d\u548c\u90e8\u9580\uff0c\u53ef\u4ee5\u9019\u6a23\u5beb\uff1a<\/p>\n<pre><code>SELECT \u59d3\u540d, \u90e8\u9580 FROM \u54e1\u5de5 WHERE \u85aa\u8cc7 &gt; 50000;<\/code><\/pre>\n<p>\u9019\u689d\u8a9e\u53e5\u5c07\u50c5\u8fd4\u56de\u85aa\u8cc7\u9ad8\u65bc 50000 \u7684\u54e1\u5de5\u7684\u59d3\u540d\u548c\u90e8\u9580\u3002<\/p>\n<h2 id=\"%e4%bd%bf%e7%94%a8%e6%8e%92%e5%ba%8f%e5%8a%9f%e8%83%bd-MyGBlPiHaA\">\u4f7f\u7528\u6392\u5e8f\u529f\u80fd<\/h2>\n<p>\u9664\u4e86\u67e5\u8a62\u7279\u5b9a\u5b57\u6bb5\u5916\uff0c\u6211\u5011\u9084\u53ef\u4ee5\u5c0d\u67e5\u8a62\u7d50\u679c\u9032\u884c\u6392\u5e8f\u3002\u4f8b\u5982\uff0c\u5982\u679c\u6211\u5011\u5e0c\u671b\u6309\u85aa\u8cc7\u5f9e\u9ad8\u5230\u4f4e\u6392\u5e8f\uff0c\u53ef\u4ee5\u4f7f\u7528 <code>ORDER BY<\/code> \u5b50\u53e5\uff1a<\/p>\n<pre><code>SELECT \u59d3\u540d, \u85aa\u8cc7 FROM \u54e1\u5de5 ORDER BY \u85aa\u8cc7 DESC;<\/code><\/pre>\n<p>\u9019\u689d\u8a9e\u53e5\u5c07\u8fd4\u56de\u6240\u6709\u54e1\u5de5\u7684\u59d3\u540d\u548c\u85aa\u8cc7\uff0c\u4e26\u6309\u85aa\u8cc7\u5f9e\u9ad8\u5230\u4f4e\u9032\u884c\u6392\u5e8f\u3002<\/p>\n<h2 id=\"%e6%9f%a5%e8%a9%a2%e5%85%a9%e5%80%8b%e5%ad%97%e6%ae%b5%e7%9a%84%e8%81%9a%e5%90%88%e5%87%bd%e6%95%b8-MyGBlPiHaA\">\u67e5\u8a62\u5169\u500b\u5b57\u6bb5\u7684\u805a\u5408\u51fd\u6578<\/h2>\n<p>\u5728\u67d0\u4e9b\u60c5\u6cc1\u4e0b\uff0c\u6211\u5011\u53ef\u80fd\u9700\u8981\u5c0d\u67e5\u8a62\u7d50\u679c\u9032\u884c\u805a\u5408\u8a08\u7b97\u3002\u4f8b\u5982\uff0c\u82e5\u8981\u8a08\u7b97\u6bcf\u500b\u90e8\u9580\u7684\u5e73\u5747\u85aa\u8cc7\uff0c\u53ef\u4ee5\u4f7f\u7528 <code>GROUP BY<\/code> \u548c\u805a\u5408\u51fd\u6578 <code>AVG()<\/code>\uff1a<\/p>\n<pre><code>SELECT \u90e8\u9580, AVG(\u85aa\u8cc7) AS \u5e73\u5747\u85aa\u8cc7 FROM \u54e1\u5de5 GROUP BY \u90e8\u9580;<\/code><\/pre>\n<p>\u9019\u689d\u8a9e\u53e5\u5c07\u8fd4\u56de\u6bcf\u500b\u90e8\u9580\u7684\u5e73\u5747\u85aa\u8cc7\u3002<\/p>\n<h2 id=\"%e7%b5%90%e8%ab%96-MyGBlPiHaA\">\u7d50\u8ad6<\/h2>\n<p>\u5728 SQL \u4e2d\uff0c\u540c\u6642\u67e5\u8a62\u5169\u500b\u5b57\u6bb5\u662f\u4e00\u500b\u57fa\u672c\u800c\u91cd\u8981\u7684\u64cd\u4f5c\u3002\u901a\u904e\u4f7f\u7528 <code>SELECT<\/code> \u8a9e\u53e5\uff0c\u6211\u5011\u53ef\u4ee5\u9748\u6d3b\u5730\u63d0\u53d6\u6240\u9700\u7684\u4fe1\u606f\uff0c\u4e26\u6839\u64da\u9700\u8981\u9032\u884c\u7be9\u9078\u548c\u6392\u5e8f\u3002\u638c\u63e1\u9019\u4e9b\u57fa\u672c\u8a9e\u6cd5\u5f8c\uff0c\u60a8\u5c07\u80fd\u5920\u66f4\u6709\u6548\u5730\u7ba1\u7406\u548c\u5206\u6790\u6578\u64da\u3002<\/p>\n<p>\u5982\u679c\u60a8\u5c0d\u65bc\u6578\u64da\u5eab\u7ba1\u7406\u6216\u5176\u4ed6\u6280\u8853\u554f\u984c\u6709\u9032\u4e00\u6b65\u7684\u9700\u6c42\uff0c\u8003\u616e\u4f7f\u7528 <a href=\"https:\/\/server.hk\">\u9999\u6e2fVPS<\/a> \u670d\u52d9\u4f86\u63d0\u5347\u60a8\u7684\u6578\u64da\u8655\u7406\u80fd\u529b\u3002\u7121\u8ad6\u662f\u642d\u5efa\u7db2\u7ad9\u9084\u662f\u9032\u884c\u6578\u64da\u5206\u6790\uff0c\u9078\u64c7\u5408\u9069\u7684 <a href=\"https:\/\/server.hk\">\u4f3a\u670d\u5668<\/a> \u90fd\u80fd\u70ba\u60a8\u7684\u696d\u52d9\u63d0\u4f9b\u5f37\u6709\u529b\u7684\u652f\u6301\u3002<\/p>\n","protected":false},"excerpt":{"rendered":"<p>\u4e86\u89e3\u5982\u4f55\u5728 SQL \u4e2d\u540c\u6642\u67e5\u8a62\u5169\u500b\u5b57\u6bb5\uff0c\u638c\u63e1\u6578\u64da\u5eab\u67e5\u8a62\u8a9e\u6cd5\uff0c\u63d0\u5347\u6578\u64da\u6aa2\u7d22\u6548\u7387\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-168441","post","type-post","status-publish","format-standard","hentry","category-database"],"_links":{"self":[{"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/posts\/168441","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=168441"}],"version-history":[{"count":1,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/posts\/168441\/revisions"}],"predecessor-version":[{"id":168442,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/posts\/168441\/revisions\/168442"}],"wp:attachment":[{"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/media?parent=168441"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/categories?post=168441"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/tags?post=168441"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}