{"id":179338,"date":"2024-11-09T00:59:19","date_gmt":"2024-11-08T16:59:19","guid":{"rendered":"https:\/\/server.hk\/cnblog\/179338\/"},"modified":"2024-11-09T00:59:20","modified_gmt":"2024-11-08T16:59:20","slug":"%e5%a6%82%e4%bd%95%e7%94%a8-sql-%e8%aa%9e%e5%8f%a5%e5%af%a6%e7%8f%be%e8%a1%a8%e6%a0%bc%e5%85%a9%e5%88%97%e7%9b%b8%e5%90%8c%e7%9a%84%e5%88%a4%e6%96%b7%ef%bc%9f-%e8%a1%a8%e6%a0%bc%e5%88%a4%e6%96%b7","status":"publish","type":"post","link":"https:\/\/server.hk\/cnblog\/179338\/","title":{"rendered":"\u5982\u4f55\u7528 SQL \u8a9e\u53e5\u5be6\u73fe\u8868\u683c\u5169\u5217\u76f8\u540c\u7684\u5224\u65b7\uff1f (\u8868\u683c\u5224\u65b7\u5169\u5217\u662f\u5426\u76f8\u540c\u7684\u6578\u64da\u5eab)"},"content":{"rendered":"<h1 id=\"%e5%a6%82%e4%bd%95%e7%94%a8-sql-%e8%aa%9e%e5%8f%a5%e5%af%a6%e7%8f%be%e8%a1%a8%e6%a0%bc%e5%85%a9%e5%88%97%e7%9b%b8%e5%90%8c%e7%9a%84%e5%88%a4%e6%96%b7%ef%bc%9f-dGSXzXOwVx\">\u5982\u4f55\u7528 SQL \u8a9e\u53e5\u5be6\u73fe\u8868\u683c\u5169\u5217\u76f8\u540c\u7684\u5224\u65b7\uff1f<\/h1>\n<p>\u5728\u6578\u64da\u5eab\u7ba1\u7406\u4e2d\uff0c\u7d93\u5e38\u9700\u8981\u5c0d\u8868\u683c\u4e2d\u7684\u6578\u64da\u9032\u884c\u6bd4\u8f03\uff0c\u4ee5\u78ba\u5b9a\u67d0\u4e9b\u5217\u7684\u503c\u662f\u5426\u76f8\u540c\u3002\u9019\u7a2e\u9700\u6c42\u5728\u6578\u64da\u6e05\u7406\u3001\u6578\u64da\u5206\u6790\u4ee5\u53ca\u5831\u544a\u751f\u6210\u4e2d\u5c24\u70ba\u91cd\u8981\u3002\u672c\u6587\u5c07\u63a2\u8a0e\u5982\u4f55\u4f7f\u7528 SQL \u8a9e\u53e5\u4f86\u5be6\u73fe\u8868\u683c\u4e2d\u5169\u5217\u76f8\u540c\u7684\u5224\u65b7\uff0c\u4e26\u63d0\u4f9b\u4e00\u4e9b\u5be6\u7528\u7684\u7bc4\u4f8b\u548c\u89e3\u91cb\u3002<\/p>\n<h2 id=\"%e5%9f%ba%e6%9c%ac%e6%a6%82%e5%bf%b5-dGSXzXOwVx\">\u57fa\u672c\u6982\u5ff5<\/h2>\n<p>\u5728 SQL \u4e2d\uff0c\u8868\u683c\u7531\u884c\u548c\u5217\u7d44\u6210\uff0c\u6bcf\u4e00\u884c\u4ee3\u8868\u4e00\u689d\u8a18\u9304\uff0c\u800c\u6bcf\u4e00\u5217\u5247\u4ee3\u8868\u8a18\u9304\u7684\u67d0\u4e00\u5c6c\u6027\u3002\u7576\u6211\u5011\u9700\u8981\u5224\u65b7\u5169\u5217\u7684\u503c\u662f\u5426\u76f8\u540c\u6642\uff0c\u53ef\u4ee5\u4f7f\u7528 SQL \u7684\u67e5\u8a62\u8a9e\u53e5\u4f86\u9032\u884c\u6bd4\u8f03\u3002\u9019\u901a\u5e38\u6d89\u53ca\u5230\u4f7f\u7528 <code>SELECT<\/code> \u8a9e\u53e5\u548c <code>WHERE<\/code> \u5b50\u53e5\u3002<\/p>\n<h2 id=\"%e4%bd%bf%e7%94%a8-sql-%e5%88%a4%e6%96%b7%e5%85%a9%e5%88%97%e6%98%af%e5%90%a6%e7%9b%b8%e5%90%8c-dGSXzXOwVx\">\u4f7f\u7528 SQL \u5224\u65b7\u5169\u5217\u662f\u5426\u76f8\u540c<\/h2>\n<p>\u5047\u8a2d\u6211\u5011\u6709\u4e00\u500b\u540d\u70ba <code>employees<\/code> \u7684\u8868\u683c\uff0c\u8a72\u8868\u683c\u5305\u542b\u4ee5\u4e0b\u5217\uff1a<\/p>\n<ul>\n<li><code>id<\/code> &#8211; \u54e1\u5de5\u7de8\u865f<\/li>\n<li><code>first_name<\/code> &#8211; \u540d\u5b57<\/li>\n<li><code>last_name<\/code> &#8211; \u59d3\u6c0f<\/li>\n<li><code>email<\/code> &#8211; \u96fb\u5b50\u90f5\u4ef6<\/li>\n<li><code>username<\/code> &#8211; \u7528\u6236\u540d<\/li>\n<\/ul>\n<p>\u5982\u679c\u6211\u5011\u60f3\u8981\u67e5\u627e <code>email<\/code> \u548c <code>username<\/code> \u5169\u5217\u7684\u503c\u662f\u5426\u76f8\u540c\uff0c\u53ef\u4ee5\u4f7f\u7528\u4ee5\u4e0b SQL \u67e5\u8a62\uff1a<\/p>\n<pre><code>SELECT *\nFROM employees\nWHERE email = username;<\/code><\/pre>\n<p>\u9019\u689d\u67e5\u8a62\u5c07\u8fd4\u56de\u6240\u6709 <code>email<\/code> \u548c <code>username<\/code> \u503c\u76f8\u540c\u7684\u8a18\u9304\u3002\u5982\u679c\u6c92\u6709\u4efb\u4f55\u8a18\u9304\u8fd4\u56de\uff0c\u5247\u8868\u793a\u9019\u5169\u5217\u7684\u503c\u5728\u6240\u6709\u884c\u4e2d\u90fd\u4e0d\u76f8\u540c\u3002<\/p>\n<h2 id=\"%e9%80%b2%e9%9a%8e%e7%94%a8%e6%b3%95%ef%bc%9a%e6%9f%a5%e6%89%be%e4%b8%8d%e7%9b%b8%e5%90%8c%e7%9a%84%e8%a8%98%e9%8c%84-dGSXzXOwVx\">\u9032\u968e\u7528\u6cd5\uff1a\u67e5\u627e\u4e0d\u76f8\u540c\u7684\u8a18\u9304<\/h2>\n<p>\u9664\u4e86\u67e5\u627e\u76f8\u540c\u7684\u8a18\u9304\u5916\uff0c\u6709\u6642\u6211\u5011\u4e5f\u9700\u8981\u627e\u51fa\u90a3\u4e9b <code>email<\/code> \u548c <code>username<\/code> \u503c\u4e0d\u76f8\u540c\u7684\u8a18\u9304\u3002\u9019\u53ef\u4ee5\u901a\u904e\u4fee\u6539 <code>WHERE<\/code> \u5b50\u53e5\u4f86\u5be6\u73fe\uff1a<\/p>\n<pre><code>SELECT *\nFROM employees\nWHERE email != username;<\/code><\/pre>\n<p>\u9019\u689d\u67e5\u8a62\u5c07\u8fd4\u56de\u6240\u6709 <code>email<\/code> \u548c <code>username<\/code> \u503c\u4e0d\u76f8\u540c\u7684\u8a18\u9304\uff0c\u9019\u5c0d\u65bc\u6578\u64da\u6e05\u7406\u548c\u9a57\u8b49\u975e\u5e38\u6709\u7528\u3002<\/p>\n<h2 id=\"%e4%bd%bf%e7%94%a8%e8%81%9a%e5%90%88%e5%87%bd%e6%95%b8%e9%80%b2%e8%a1%8c%e7%b5%b1%e8%a8%88-dGSXzXOwVx\">\u4f7f\u7528\u805a\u5408\u51fd\u6578\u9032\u884c\u7d71\u8a08<\/h2>\n<p>\u5728\u67d0\u4e9b\u60c5\u6cc1\u4e0b\uff0c\u6211\u5011\u53ef\u80fd\u5e0c\u671b\u7372\u5f97\u66f4\u8a73\u7d30\u7684\u7d71\u8a08\u4fe1\u606f\uff0c\u4f8b\u5982\u6709\u591a\u5c11\u689d\u8a18\u9304\u7684 <code>email<\/code> \u548c <code>username<\/code> \u503c\u76f8\u540c\u3002\u9019\u53ef\u4ee5\u901a\u904e\u4f7f\u7528\u805a\u5408\u51fd\u6578 <code>COUNT<\/code> \u4f86\u5be6\u73fe\uff1a<\/p>\n<pre><code>SELECT COUNT(*) AS matching_records\nFROM employees\nWHERE email = username;<\/code><\/pre>\n<p>\u9019\u689d\u67e5\u8a62\u5c07\u8fd4\u56de\u4e00\u500b\u6578\u5b57\uff0c\u8868\u793a <code>email<\/code> \u548c <code>username<\/code> \u503c\u76f8\u540c\u7684\u8a18\u9304\u6578\u91cf\u3002<\/p>\n<h2 id=\"%e7%b5%90%e8%ab%96-dGSXzXOwVx\">\u7d50\u8ad6<\/h2>\n<p>\u901a\u904e\u4f7f\u7528 SQL \u8a9e\u53e5\uff0c\u6211\u5011\u53ef\u4ee5\u8f15\u9b06\u5730\u5224\u65b7\u8868\u683c\u4e2d\u5169\u5217\u7684\u503c\u662f\u5426\u76f8\u540c\u3002\u7121\u8ad6\u662f\u67e5\u627e\u76f8\u540c\u7684\u8a18\u9304\u9084\u662f\u4e0d\u76f8\u540c\u7684\u8a18\u9304\uff0cSQL \u90fd\u63d0\u4f9b\u4e86\u9748\u6d3b\u7684\u67e5\u8a62\u65b9\u5f0f\u4f86\u6eff\u8db3\u4e0d\u540c\u7684\u9700\u6c42\u3002\u638c\u63e1\u9019\u4e9b\u57fa\u672c\u7684 SQL \u67e5\u8a62\u6280\u5de7\uff0c\u5c07\u6709\u52a9\u65bc\u63d0\u9ad8\u6578\u64da\u8655\u7406\u7684\u6548\u7387\u548c\u6e96\u78ba\u6027\u3002<\/p>\n<p>\u5982\u679c\u60a8\u5c0d\u65bc\u6578\u64da\u5eab\u7ba1\u7406\u6709\u66f4\u6df1\u5165\u7684\u9700\u6c42\uff0c\u8003\u616e\u4f7f\u7528 <a href=\"https:\/\/server.hk\">\u9999\u6e2fVPS<\/a> \u4f86\u642d\u5efa\u60a8\u7684\u6578\u64da\u5eab\u74b0\u5883\uff0c\u4eab\u53d7\u66f4\u9ad8\u7684\u6027\u80fd\u548c\u7a69\u5b9a\u6027\u3002<\/p>\n","protected":false},"excerpt":{"rendered":"<p>\u5b78\u7fd2\u5982\u4f55\u4f7f\u7528 SQL \u8a9e\u53e5\u5224\u65b7\u6578\u64da\u5eab\u8868\u683c\u4e2d\u5169\u5217\u662f\u5426\u76f8\u540c\uff0c\u7c21\u5316\u6578\u64da\u6bd4\u8f03\u8207\u5206\u6790\u904e\u7a0b\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-179338","post","type-post","status-publish","format-standard","hentry","category-database"],"_links":{"self":[{"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/posts\/179338","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=179338"}],"version-history":[{"count":1,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/posts\/179338\/revisions"}],"predecessor-version":[{"id":179339,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/posts\/179338\/revisions\/179339"}],"wp:attachment":[{"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/media?parent=179338"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/categories?post=179338"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/tags?post=179338"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}