{"id":179704,"date":"2024-11-09T04:06:18","date_gmt":"2024-11-08T20:06:18","guid":{"rendered":"https:\/\/server.hk\/cnblog\/179704\/"},"modified":"2024-11-09T04:06:19","modified_gmt":"2024-11-08T20:06:19","slug":"%e5%a6%82%e4%bd%95%e5%9c%a8-sql-%e6%95%b8%e6%93%9a%e5%ba%ab%e4%b8%ad%e8%a8%ad%e7%bd%ae%e4%b9%98%e6%b3%95%e6%93%8d%e4%bd%9c-sql-%e6%95%b8%e6%93%9a%e5%ba%ab%e4%b8%ad%e8%a8%ad%e7%bd%ae%e4%b9%98%e6%b3%95","status":"publish","type":"post","link":"https:\/\/server.hk\/cnblog\/179704\/","title":{"rendered":"\u5982\u4f55\u5728 SQL \u6578\u64da\u5eab\u4e2d\u8a2d\u7f6e\u4e58\u6cd5\u64cd\u4f5c (sql \u6578\u64da\u5eab\u4e2d\u8a2d\u7f6e\u4e58\u6cd5)"},"content":{"rendered":"<h1 id=\"%e5%a6%82%e4%bd%95%e5%9c%a8-sql-%e6%95%b8%e6%93%9a%e5%ba%ab%e4%b8%ad%e8%a8%ad%e7%bd%ae%e4%b9%98%e6%b3%95%e6%93%8d%e4%bd%9c-lGhQeslqYy\">\u5982\u4f55\u5728 SQL \u6578\u64da\u5eab\u4e2d\u8a2d\u7f6e\u4e58\u6cd5\u64cd\u4f5c<\/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\u4e58\u6cd5\u64cd\u4f5c\u662f\u6578\u64da\u8655\u7406\u4e2d\u7684\u4e00\u500b\u57fa\u672c\u529f\u80fd\uff0c\u5c24\u5176\u5728\u9700\u8981\u8a08\u7b97\u7e3d\u50f9\u3001\u6298\u6263\u6216\u5176\u4ed6\u6578\u5b78\u904b\u7b97\u6642\uff0c\u4e58\u6cd5\u64cd\u4f5c\u986f\u5f97\u5c24\u70ba\u91cd\u8981\u3002\u672c\u6587\u5c07\u4ecb\u7d39\u5982\u4f55\u5728 SQL \u6578\u64da\u5eab\u4e2d\u8a2d\u7f6e\u4e58\u6cd5\u64cd\u4f5c\uff0c\u4e26\u63d0\u4f9b\u76f8\u95dc\u7684\u793a\u4f8b\u548c\u4ee3\u78bc\u7247\u6bb5\u3002<\/p>\n<h2 id=\"%e5%9f%ba%e6%9c%ac%e7%9a%84%e4%b9%98%e6%b3%95%e6%93%8d%e4%bd%9c-lGhQeslqYy\">\u57fa\u672c\u7684\u4e58\u6cd5\u64cd\u4f5c<\/h2>\n<p>\u5728 SQL \u4e2d\uff0c\u4e58\u6cd5\u64cd\u4f5c\u53ef\u4ee5\u901a\u904e\u4f7f\u7528\u661f\u865f\uff08*\uff09\u4f86\u5be6\u73fe\u3002\u9019\u500b\u64cd\u4f5c\u7b26\u53ef\u4ee5\u7528\u65bc\u6578\u5b57\u985e\u578b\u7684\u5b57\u6bb5\uff0c\u4e26\u4e14\u53ef\u4ee5\u5728 SELECT \u8a9e\u53e5\u4e2d\u76f4\u63a5\u4f7f\u7528\u3002\u4ee5\u4e0b\u662f\u4e00\u500b\u7c21\u55ae\u7684\u793a\u4f8b\uff0c\u5c55\u793a\u5982\u4f55\u5728\u67e5\u8a62\u4e2d\u9032\u884c\u4e58\u6cd5\u904b\u7b97\uff1a<\/p>\n<pre><code>SELECT \u5546\u54c1\u540d\u7a31, \u50f9\u683c, \u6578\u91cf, \u50f9\u683c * \u6578\u91cf AS \u7e3d\u50f9\nFROM \u5546\u54c1\u8868;<\/code><\/pre>\n<p>\u5728\u9019\u500b\u4f8b\u5b50\u4e2d\uff0c\u6211\u5011\u5f9e\u540d\u70ba\u201c\u5546\u54c1\u8868\u201d\u7684\u8868\u4e2d\u9078\u64c7\u4e86\u5546\u54c1\u540d\u7a31\u3001\u50f9\u683c\u548c\u6578\u91cf\uff0c\u4e26\u8a08\u7b97\u4e86\u7e3d\u50f9\u3002\u9019\u88e1\u7684\u201c\u7e3d\u50f9\u201d\u662f\u901a\u904e\u5c07\u50f9\u683c\u548c\u6578\u91cf\u76f8\u4e58\u5f97\u51fa\u7684\u3002<\/p>\n<h2 id=\"%e4%bd%bf%e7%94%a8%e4%b9%98%e6%b3%95%e6%93%8d%e4%bd%9c%e9%80%b2%e8%a1%8c%e6%95%b8%e6%93%9a%e6%9b%b4%e6%96%b0-lGhQeslqYy\">\u4f7f\u7528\u4e58\u6cd5\u64cd\u4f5c\u9032\u884c\u6578\u64da\u66f4\u65b0<\/h2>\n<p>\u9664\u4e86\u5728\u67e5\u8a62\u4e2d\u4f7f\u7528\u4e58\u6cd5\u64cd\u4f5c\u5916\uff0c\u6211\u5011\u9084\u53ef\u4ee5\u5728 UPDATE \u8a9e\u53e5\u4e2d\u4f7f\u7528\u5b83\u4f86\u66f4\u65b0\u8868\u4e2d\u7684\u6578\u64da\u3002\u4f8b\u5982\uff0c\u5047\u8a2d\u6211\u5011\u9700\u8981\u5c07\u6240\u6709\u5546\u54c1\u7684\u50f9\u683c\u63d0\u9ad8 10%\uff0c\u53ef\u4ee5\u4f7f\u7528\u4ee5\u4e0b SQL \u8a9e\u53e5\uff1a<\/p>\n<pre><code>UPDATE \u5546\u54c1\u8868\nSET \u50f9\u683c = \u50f9\u683c * 1.1;<\/code><\/pre>\n<p>\u9019\u689d\u8a9e\u53e5\u5c07\u5546\u54c1\u8868\u4e2d\u6240\u6709\u5546\u54c1\u7684\u50f9\u683c\u4e58\u4ee5 1.1\uff0c\u5f9e\u800c\u5be6\u73fe\u50f9\u683c\u7684\u63d0\u5347\u3002<\/p>\n<h2 id=\"%e5%9c%a8-where-%e5%ad%90%e5%8f%a5%e4%b8%ad%e4%bd%bf%e7%94%a8%e4%b9%98%e6%b3%95-lGhQeslqYy\">\u5728 WHERE \u5b50\u53e5\u4e2d\u4f7f\u7528\u4e58\u6cd5<\/h2>\n<p>\u6709\u6642\u5019\uff0c\u6211\u5011\u53ef\u80fd\u9700\u8981\u6839\u64da\u8a08\u7b97\u7d50\u679c\u4f86\u7be9\u9078\u6578\u64da\u3002\u5728\u9019\u7a2e\u60c5\u6cc1\u4e0b\uff0c\u6211\u5011\u53ef\u4ee5\u5728 WHERE \u5b50\u53e5\u4e2d\u4f7f\u7528\u4e58\u6cd5\u64cd\u4f5c\u3002\u4f8b\u5982\uff0c\u5047\u8a2d\u6211\u5011\u53ea\u60f3\u67e5\u8a62\u7e3d\u50f9\u8d85\u904e 100 \u7684\u5546\u54c1\uff0c\u53ef\u4ee5\u4f7f\u7528\u4ee5\u4e0b\u67e5\u8a62\uff1a<\/p>\n<pre><code>SELECT \u5546\u54c1\u540d\u7a31, \u50f9\u683c, \u6578\u91cf\nFROM \u5546\u54c1\u8868\nWHERE \u50f9\u683c * \u6578\u91cf &gt; 100;<\/code><\/pre>\n<p>\u9019\u689d\u67e5\u8a62\u5c07\u8fd4\u56de\u6240\u6709\u7e3d\u50f9\u8d85\u904e 100 \u7684\u5546\u54c1\u3002<\/p>\n<h2 id=\"%e5%a4%9a%e8%a1%a8%e8%81%af%e6%8e%a5%e4%b8%ad%e7%9a%84%e4%b9%98%e6%b3%95%e6%93%8d%e4%bd%9c-lGhQeslqYy\">\u591a\u8868\u806f\u63a5\u4e2d\u7684\u4e58\u6cd5\u64cd\u4f5c<\/h2>\n<p>\u5728\u9032\u884c\u591a\u8868\u806f\u63a5\u6642\uff0c\u6211\u5011\u4e5f\u53ef\u4ee5\u4f7f\u7528\u4e58\u6cd5\u64cd\u4f5c\u4f86\u8a08\u7b97\u76f8\u95dc\u6578\u64da\u3002\u4f8b\u5982\uff0c\u5047\u8a2d\u6211\u5011\u6709\u5169\u500b\u8868\uff1a\u4e00\u500b\u662f\u201c\u5546\u54c1\u8868\u201d\uff0c\u53e6\u4e00\u500b\u662f\u201c\u6298\u6263\u8868\u201d\u3002\u6211\u5011\u5e0c\u671b\u8a08\u7b97\u6bcf\u500b\u5546\u54c1\u7684\u6298\u6263\u5f8c\u50f9\u683c\uff0c\u53ef\u4ee5\u4f7f\u7528\u4ee5\u4e0b\u67e5\u8a62\uff1a<\/p>\n<pre><code>SELECT g.\u5546\u54c1\u540d\u7a31, g.\u50f9\u683c, d.\u6298\u6263\u7387, g.\u50f9\u683c * (1 - d.\u6298\u6263\u7387) AS \u6298\u6263\u5f8c\u50f9\u683c\nFROM \u5546\u54c1\u8868 g\nJOIN \u6298\u6263\u8868 d ON g.\u5546\u54c1ID = d.\u5546\u54c1ID;<\/code><\/pre>\n<p>\u9019\u689d\u67e5\u8a62\u5c07\u8fd4\u56de\u6bcf\u500b\u5546\u54c1\u7684\u540d\u7a31\u3001\u539f\u50f9\u3001\u6298\u6263\u7387\u4ee5\u53ca\u6298\u6263\u5f8c\u7684\u50f9\u683c\u3002<\/p>\n<h2 id=\"%e6%b3%a8%e6%84%8f%e4%ba%8b%e9%a0%85-lGhQeslqYy\">\u6ce8\u610f\u4e8b\u9805<\/h2>\n<p>\u5728\u9032\u884c\u4e58\u6cd5\u64cd\u4f5c\u6642\uff0c\u6709\u5e7e\u9ede\u9700\u8981\u6ce8\u610f\uff1a<\/p>\n<ul>\n<li>\u78ba\u4fdd\u53c3\u8207\u904b\u7b97\u7684\u5b57\u6bb5\u70ba\u6578\u5b57\u985e\u578b\uff0c\u5426\u5247\u53ef\u80fd\u6703\u5c0e\u81f4\u932f\u8aa4\u3002<\/li>\n<li>\u5728\u9032\u884c\u5927\u6578\u64da\u91cf\u7684\u8a08\u7b97\u6642\uff0c\u6ce8\u610f\u6027\u80fd\u554f\u984c\uff0c\u907f\u514d\u5f71\u97ff\u67e5\u8a62\u6548\u7387\u3002<\/li>\n<li>\u5728\u4f7f\u7528\u4e58\u6cd5\u64cd\u4f5c\u6642\uff0c\u8003\u616e\u5230\u53ef\u80fd\u7684 NULL \u503c\uff0c\u9019\u53ef\u80fd\u6703\u5f71\u97ff\u8a08\u7b97\u7d50\u679c\u3002<\/li>\n<\/ul>\n<h2 id=\"%e7%b8%bd%e7%b5%90-lGhQeslqYy\">\u7e3d\u7d50<\/h2>\n<p>\u5728 SQL \u6578\u64da\u5eab\u4e2d\u8a2d\u7f6e\u4e58\u6cd5\u64cd\u4f5c\u662f\u4e00\u500b\u57fa\u672c\u800c\u91cd\u8981\u7684\u6280\u80fd\uff0c\u7121\u8ad6\u662f\u5728\u67e5\u8a62\u3001\u66f4\u65b0\u9084\u662f\u591a\u8868\u806f\u63a5\u4e2d\u90fd\u80fd\u767c\u63ee\u4f5c\u7528\u3002\u901a\u904e\u672c\u6587\u7684\u4ecb\u7d39\uff0c\u60a8\u61c9\u8a72\u80fd\u5920\u719f\u7df4\u5730\u5728 SQL \u4e2d\u4f7f\u7528\u4e58\u6cd5\u64cd\u4f5c\u4f86\u8655\u7406\u5404\u7a2e\u6578\u64da\u8a08\u7b97\u9700\u6c42\u3002\u5982\u679c\u60a8\u9700\u8981\u66f4\u9ad8\u6548\u7684\u6578\u64da\u8655\u7406\u548c\u7ba1\u7406\uff0c\u8003\u616e\u4f7f\u7528<a href=\"https:\/\/server.hk\">\u9999\u6e2fVPS<\/a>\u6216<a href=\"https:\/\/server.hk\">\u4e91\u670d\u52a1\u5668<\/a>\u4f86\u63d0\u5347\u60a8\u7684\u6578\u64da\u5eab\u6027\u80fd\u548c\u7a69\u5b9a\u6027\u3002<\/p>\n","protected":false},"excerpt":{"rendered":"<p>\u5b78\u7fd2\u5982\u4f55\u5728 SQL \u6578\u64da\u5eab\u4e2d\u8a2d\u7f6e\u4e58\u6cd5\u64cd\u4f5c\uff0c\u638c\u63e1\u57fa\u672c\u8a9e\u6cd5\u548c\u5be6\u7528\u7bc4\u4f8b\uff0c\u63d0\u5347\u6578\u64da\u8655\u7406\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-179704","post","type-post","status-publish","format-standard","hentry","category-database"],"_links":{"self":[{"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/posts\/179704","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=179704"}],"version-history":[{"count":1,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/posts\/179704\/revisions"}],"predecessor-version":[{"id":179705,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/posts\/179704\/revisions\/179705"}],"wp:attachment":[{"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/media?parent=179704"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/categories?post=179704"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/tags?post=179704"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}