{"id":71133,"date":"2024-10-15T14:47:15","date_gmt":"2024-10-15T06:47:15","guid":{"rendered":"https:\/\/server.hk\/cnblog\/71133\/"},"modified":"2024-10-15T14:47:15","modified_gmt":"2024-10-15T06:47:15","slug":"mssql%e4%b8%ad%e7%9a%84%e6%a2%9d%e4%bb%b6%e5%88%a4%e6%96%b7%ef%bc%9a%e5%af%a6%e7%8f%be%e9%ab%98%e6%95%88%e9%81%8b%e7%ae%97%ef%bc%88mssql%e6%a2%9d%e4%bb%b6%e5%88%a4%e6%96%b7%ef%bc%89","status":"publish","type":"post","link":"https:\/\/server.hk\/cnblog\/71133\/","title":{"rendered":"MSSQL\u4e2d\u7684\u689d\u4ef6\u5224\u65b7\uff1a\u5be6\u73fe\u9ad8\u6548\u904b\u7b97\uff08mssql\u689d\u4ef6\u5224\u65b7\uff09"},"content":{"rendered":"<h1 id=\"mssql%e4%b8%ad%e7%9a%84%e6%a2%9d%e4%bb%b6%e5%88%a4%e6%96%b7%ef%bc%9a%e5%af%a6%e7%8f%be%e9%ab%98%e6%95%88%e9%81%8b%e7%ae%97-TKhzmAeyrT\">MSSQL\u4e2d\u7684\u689d\u4ef6\u5224\u65b7\uff1a\u5be6\u73fe\u9ad8\u6548\u904b\u7b97<\/h1>\n<p>\u5728\u6578\u64da\u5eab\u7ba1\u7406\u7cfb\u7d71\u4e2d\uff0c\u689d\u4ef6\u5224\u65b7\u662f\u4e00\u500b\u81f3\u95dc\u91cd\u8981\u7684\u529f\u80fd\uff0c\u5c24\u5176\u662f\u5728\u4f7f\u7528Microsoft SQL Server\uff08MSSQL\uff09\u6642\u3002\u900f\u904e\u6709\u6548\u7684\u689d\u4ef6\u5224\u65b7\uff0c\u6211\u5011\u53ef\u4ee5\u512a\u5316\u67e5\u8a62\u6027\u80fd\uff0c\u63d0\u5347\u6578\u64da\u8655\u7406\u7684\u6548\u7387\u3002\u672c\u6587\u5c07\u63a2\u8a0eMSSQL\u4e2d\u7684\u689d\u4ef6\u5224\u65b7\uff0c\u4e26\u63d0\u4f9b\u4e00\u4e9b\u5be6\u7528\u7684\u793a\u4f8b\u548c\u6700\u4f73\u5be6\u8e10\u3002<\/p>\n<h2 id=\"%e4%bb%80%e9%ba%bc%e6%98%af%e6%a2%9d%e4%bb%b6%e5%88%a4%e6%96%b7%ef%bc%9f-TKhzmAeyrT\">\u4ec0\u9ebc\u662f\u689d\u4ef6\u5224\u65b7\uff1f<\/h2>\n<p>\u689d\u4ef6\u5224\u65b7\u662f\u6307\u6839\u64da\u7279\u5b9a\u689d\u4ef6\u4f86\u6c7a\u5b9a\u57f7\u884c\u67d0\u4e9b\u64cd\u4f5c\u7684\u904e\u7a0b\u3002\u5728MSSQL\u4e2d\uff0c\u9019\u901a\u5e38\u6d89\u53ca\u5230\u4f7f\u7528SQL\u8a9e\u53e5\u4e2d\u7684\u908f\u8f2f\u904b\u7b97\u7b26\u548c\u63a7\u5236\u6d41\u8a9e\u53e5\u3002\u9019\u4e9b\u689d\u4ef6\u53ef\u4ee5\u662f\u7c21\u55ae\u7684\u6bd4\u8f03\uff0c\u4e5f\u53ef\u4ee5\u662f\u8907\u96dc\u7684\u908f\u8f2f\u904b\u7b97\u3002<\/p>\n<h2 id=\"mssql%e4%b8%ad%e7%9a%84%e6%a2%9d%e4%bb%b6%e5%88%a4%e6%96%b7%e8%aa%9e%e5%8f%a5-TKhzmAeyrT\">MSSQL\u4e2d\u7684\u689d\u4ef6\u5224\u65b7\u8a9e\u53e5<\/h2>\n<p>MSSQL\u63d0\u4f9b\u4e86\u591a\u7a2e\u65b9\u5f0f\u4f86\u5be6\u73fe\u689d\u4ef6\u5224\u65b7\uff0c\u4ee5\u4e0b\u662f\u5e7e\u500b\u5e38\u7528\u7684\u8a9e\u53e5\uff1a<\/p>\n<h3 id=\"1-case%e8%aa%9e%e5%8f%a5-TKhzmAeyrT\">1. CASE\u8a9e\u53e5<\/h3>\n<p>CASE\u8a9e\u53e5\u662f\u4e00\u7a2e\u975e\u5e38\u9748\u6d3b\u7684\u689d\u4ef6\u5224\u65b7\u5de5\u5177\uff0c\u53ef\u4ee5\u5728SELECT\u3001UPDATE\u548cDELETE\u8a9e\u53e5\u4e2d\u4f7f\u7528\u3002\u5b83\u7684\u57fa\u672c\u8a9e\u6cd5\u5982\u4e0b\uff1a<\/p>\n<pre><code>SELECT \n    column1,\n    CASE \n        WHEN condition1 THEN result1\n        WHEN condition2 THEN result2\n        ELSE result_default\n    END AS alias_name\nFROM table_name;<\/code><\/pre>\n<p>\u4f8b\u5982\uff0c\u5047\u8a2d\u6211\u5011\u6709\u4e00\u500b\u54e1\u5de5\u8868\uff0c\u60f3\u8981\u6839\u64da\u85aa\u6c34\u7bc4\u570d\u4f86\u5206\u985e\u54e1\u5de5\uff1a<\/p>\n<pre><code>SELECT \n    EmployeeName,\n    Salary,\n    CASE \n        WHEN Salary &gt;= 100000 THEN '\u9ad8\u85aa'\n        WHEN Salary &gt;= 50000 THEN '\u4e2d\u85aa'\n        ELSE '\u4f4e\u85aa'\n    END AS SalaryCategory\nFROM Employees;<\/code><\/pre>\n<h3 id=\"2-if-else%e8%aa%9e%e5%8f%a5-TKhzmAeyrT\">2. IF&#8230;ELSE\u8a9e\u53e5<\/h3>\n<p>IF&#8230;ELSE\u8a9e\u53e5\u7528\u65bc\u63a7\u5236\u6d41\uff0c\u6839\u64da\u689d\u4ef6\u57f7\u884c\u4e0d\u540c\u7684\u64cd\u4f5c\u3002\u5176\u57fa\u672c\u8a9e\u6cd5\u5982\u4e0b\uff1a<\/p>\n<pre><code>IF condition\nBEGIN\n    -- \u57f7\u884c\u67d0\u4e9b\u64cd\u4f5c\nEND\nELSE\nBEGIN\n    -- \u57f7\u884c\u5176\u4ed6\u64cd\u4f5c\nEND;<\/code><\/pre>\n<p>\u4f8b\u5982\uff0c\u6839\u64da\u54e1\u5de5\u7684\u5e74\u9f61\u4f86\u6c7a\u5b9a\u662f\u5426\u53ef\u4ee5\u53c3\u52a0\u9000\u4f11\u8a08\u5283\uff1a<\/p>\n<pre><code>IF Age &gt;= 60\nBEGIN\n    PRINT '\u7b26\u5408\u9000\u4f11\u689d\u4ef6';\nEND\nELSE\nBEGIN\n    PRINT '\u4e0d\u7b26\u5408\u9000\u4f11\u689d\u4ef6';\nEND;<\/code><\/pre>\n<h3 id=\"3-where%e5%ad%90%e5%8f%a5%e4%b8%ad%e7%9a%84%e6%a2%9d%e4%bb%b6%e5%88%a4%e6%96%b7-TKhzmAeyrT\">3. WHERE\u5b50\u53e5\u4e2d\u7684\u689d\u4ef6\u5224\u65b7<\/h3>\n<p>\u5728\u67e5\u8a62\u6578\u64da\u6642\uff0cWHERE\u5b50\u53e5\u53ef\u4ee5\u7528\u4f86\u904e\u6ffe\u7d50\u679c\u96c6\u3002\u9019\u88e1\u7684\u689d\u4ef6\u5224\u65b7\u53ef\u4ee5\u662f\u591a\u500b\u689d\u4ef6\u7684\u7d44\u5408\uff1a<\/p>\n<pre><code>SELECT * \nFROM Employees \nWHERE Salary &gt; 50000 AND Age &lt; 40;<\/code><\/pre>\n<h2 id=\"%e6%9c%80%e4%bd%b3%e5%af%a6%e8%b8%90-TKhzmAeyrT\">\u6700\u4f73\u5be6\u8e10<\/h2>\n<ul>\n<li><strong>\u7c21\u5316\u689d\u4ef6\uff1a<\/strong>\u76e1\u91cf\u7c21\u5316\u689d\u4ef6\u5224\u65b7\uff0c\u907f\u514d\u904e\u65bc\u8907\u96dc\u7684\u908f\u8f2f\uff0c\u9019\u6a23\u53ef\u4ee5\u63d0\u9ad8\u67e5\u8a62\u6027\u80fd\u3002<\/li>\n<li><strong>\u4f7f\u7528\u7d22\u5f15\uff1a<\/strong>\u5728\u6d89\u53ca\u5230\u689d\u4ef6\u5224\u65b7\u7684\u5217\u4e0a\u5efa\u7acb\u7d22\u5f15\uff0c\u53ef\u4ee5\u986f\u8457\u63d0\u9ad8\u67e5\u8a62\u901f\u5ea6\u3002<\/li>\n<li><strong>\u907f\u514d\u4f7f\u7528SELECT *\uff1a<\/strong>\u5728\u67e5\u8a62\u4e2d\u660e\u78ba\u6307\u5b9a\u9700\u8981\u7684\u5217\uff0c\u9019\u6a23\u53ef\u4ee5\u6e1b\u5c11\u6578\u64da\u50b3\u8f38\u91cf\u3002<\/li>\n<\/ul>\n<h2 id=\"%e7%b5%90%e8%ab%96-TKhzmAeyrT\">\u7d50\u8ad6<\/h2>\n<p>MSSQL\u4e2d\u7684\u689d\u4ef6\u5224\u65b7\u662f\u5be6\u73fe\u9ad8\u6548\u904b\u7b97\u7684\u95dc\u9375\u3002\u900f\u904e\u5408\u7406\u4f7f\u7528CASE\u8a9e\u53e5\u3001IF&#8230;ELSE\u8a9e\u53e5\u548cWHERE\u5b50\u53e5\uff0c\u6211\u5011\u53ef\u4ee5\u512a\u5316\u6578\u64da\u67e5\u8a62\u548c\u8655\u7406\u7684\u6548\u7387\u3002\u638c\u63e1\u9019\u4e9b\u6280\u5de7\u4e0d\u50c5\u80fd\u63d0\u5347\u958b\u767c\u6548\u7387\uff0c\u9084\u80fd\u6539\u5584\u7cfb\u7d71\u6027\u80fd\u3002<\/p>\n<p>\u5982\u9700\u4e86\u89e3\u66f4\u591a\u95dc\u65bc<code><a href=\"https:\/\/server.hk\">\u9999\u6e2fVPS<\/a><\/code>\u548c<code><a href=\"https:\/\/server.hk\">\u96f2\u4f3a\u670d\u5668<\/a><\/code>\u7684\u8cc7\u8a0a\uff0c\u8acb\u8a2a\u554f\u6211\u5011\u7684\u7db2\u7ad9\u3002<\/p>\n","protected":false},"excerpt":{"rendered":"<p>\u63a2\u7d22MSSQL\u4e2d\u7684\u689d\u4ef6\u5224\u65b7\u6280\u8853\uff0c\u63d0\u5347\u67e5\u8a62\u6548\u7387\uff0c\u5be6\u73fe\u9ad8\u6548\u904b\u7b97\uff0c\u512a\u5316\u6578\u64da\u8655\u7406\u6d41\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-71133","post","type-post","status-publish","format-standard","hentry","category-database"],"_links":{"self":[{"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/posts\/71133","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=71133"}],"version-history":[{"count":1,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/posts\/71133\/revisions"}],"predecessor-version":[{"id":71134,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/posts\/71133\/revisions\/71134"}],"wp:attachment":[{"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/media?parent=71133"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/categories?post=71133"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/tags?post=71133"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}