{"id":168823,"date":"2024-11-06T16:31:37","date_gmt":"2024-11-06T08:31:37","guid":{"rendered":"https:\/\/server.hk\/cnblog\/168823\/"},"modified":"2024-11-06T16:31:38","modified_gmt":"2024-11-06T08:31:38","slug":"t-sql-%e6%9f%a5%e8%a9%a2%e9%80%b2%e9%9a%8e%e4%b9%8b%e6%b7%b1%e5%85%a5%e7%90%86%e8%a7%a3%e5%ad%90%e6%9f%a5%e8%a9%a2","status":"publish","type":"post","link":"https:\/\/server.hk\/cnblog\/168823\/","title":{"rendered":"T-SQL \u67e5\u8a62\u9032\u968e\u4e4b\u6df1\u5165\u7406\u89e3\u5b50\u67e5\u8a62"},"content":{"rendered":"<h1 id=\"t-sql-%e6%9f%a5%e8%a9%a2%e9%80%b2%e9%9a%8e%e4%b9%8b%e6%b7%b1%e5%85%a5%e7%90%86%e8%a7%a3%e5%ad%90%e6%9f%a5%e8%a9%a2-GaWLomavxI\">T-SQL \u67e5\u8a62\u9032\u968e\u4e4b\u6df1\u5165\u7406\u89e3\u5b50\u67e5\u8a62<\/h1>\n<p>\u5728\u8cc7\u6599\u5eab\u7ba1\u7406\u7cfb\u7d71\u4e2d\uff0cT-SQL\uff08Transact-SQL\uff09\u662f Microsoft SQL Server \u7684\u64f4\u5c55 SQL \u8a9e\u8a00\uff0c\u63d0\u4f9b\u4e86\u5f37\u5927\u7684\u67e5\u8a62\u529f\u80fd\u3002\u5b50\u67e5\u8a62\u662f T-SQL \u4e2d\u4e00\u500b\u91cd\u8981\u7684\u6982\u5ff5\uff0c\u80fd\u5920\u5e6b\u52a9\u958b\u767c\u8005\u5728\u67e5\u8a62\u4e2d\u5d4c\u5957\u5176\u4ed6\u67e5\u8a62\uff0c\u4ee5\u9054\u5230\u66f4\u8907\u96dc\u7684\u8cc7\u6599\u6aa2\u7d22\u9700\u6c42\u3002\u672c\u6587\u5c07\u6df1\u5165\u63a2\u8a0e\u5b50\u67e5\u8a62\u7684\u6982\u5ff5\u3001\u985e\u578b\u53ca\u5176\u4f7f\u7528\u65b9\u6cd5\uff0c\u4e26\u63d0\u4f9b\u5be6\u969b\u7684\u7bc4\u4f8b\u4f86\u5e6b\u52a9\u8b80\u8005\u66f4\u597d\u5730\u7406\u89e3\u9019\u4e00\u4e3b\u984c\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-GaWLomavxI\">\u4ec0\u9ebc\u662f\u5b50\u67e5\u8a62\uff1f<\/h2>\n<p>\u5b50\u67e5\u8a62\u662f\u6307\u5728\u4e00\u500b\u67e5\u8a62\u4e2d\u5d4c\u5957\u7684\u53e6\u4e00\u500b\u67e5\u8a62\u3002\u5b83\u53ef\u4ee5\u51fa\u73fe\u5728 SELECT\u3001INSERT\u3001UPDATE \u6216 DELETE \u8a9e\u53e5\u4e2d\uff0c\u4e26\u4e14\u53ef\u4ee5\u7528\u4f86\u8fd4\u56de\u55ae\u4e00\u503c\u3001\u884c\u6216\u591a\u884c\u8cc7\u6599\u3002\u5b50\u67e5\u8a62\u7684\u4e3b\u8981\u76ee\u7684\u662f\u5728\u4e3b\u67e5\u8a62\u4e2d\u63d0\u4f9b\u984d\u5916\u7684\u689d\u4ef6\u6216\u8cc7\u6599\uff0c\u5f9e\u800c\u4f7f\u67e5\u8a62\u7d50\u679c\u66f4\u52a0\u7cbe\u78ba\u3002<\/p>\n<h2 id=\"%e5%ad%90%e6%9f%a5%e8%a9%a2%e7%9a%84%e9%a1%9e%e5%9e%8b-GaWLomavxI\">\u5b50\u67e5\u8a62\u7684\u985e\u578b<\/h2>\n<p>\u5b50\u67e5\u8a62\u4e3b\u8981\u53ef\u4ee5\u5206\u70ba\u4ee5\u4e0b\u5e7e\u7a2e\u985e\u578b\uff1a<\/p>\n<ul>\n<li><strong>\u55ae\u884c\u5b50\u67e5\u8a62\uff1a<\/strong>\u8fd4\u56de\u55ae\u4e00\u884c\u7684\u7d50\u679c\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\u7684\u7d50\u679c\uff0c\u901a\u5e38\u7528\u65bc IN \u6216 EXISTS \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\u8cc7\u6599\uff0c\u901a\u5e38\u5728 WHERE \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\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%af%84%e4%be%8b-GaWLomavxI\">\u5b50\u67e5\u8a62\u7684\u4f7f\u7528\u7bc4\u4f8b<\/h2>\n<p>\u4ee5\u4e0b\u662f\u4e00\u4e9b\u4f7f\u7528\u5b50\u67e5\u8a62\u7684\u7bc4\u4f8b\uff0c\u5e6b\u52a9\u8b80\u8005\u7406\u89e3\u5176\u7528\u6cd5\uff1a<\/p>\n<h3 id=\"1-%e5%96%ae%e8%a1%8c%e5%ad%90%e6%9f%a5%e8%a9%a2%e7%af%84%e4%be%8b-GaWLomavxI\">1. \u55ae\u884c\u5b50\u67e5\u8a62\u7bc4\u4f8b<\/h3>\n<pre><code>SELECT EmployeeID, FirstName, LastName\nFROM Employees\nWHERE Salary &gt; (SELECT AVG(Salary) FROM Employees);<\/code><\/pre>\n<p>\u5728\u9019\u500b\u7bc4\u4f8b\u4e2d\uff0c\u6211\u5011\u67e5\u8a62\u6240\u6709\u85aa\u6c34\u9ad8\u65bc\u5e73\u5747\u85aa\u6c34\u7684\u54e1\u5de5\u3002\u5167\u90e8\u7684\u5b50\u67e5\u8a62\u8a08\u7b97\u4e86\u6240\u6709\u54e1\u5de5\u7684\u5e73\u5747\u85aa\u6c34\uff0c\u4e26\u5c07\u5176\u4f5c\u70ba\u689d\u4ef6\u4f7f\u7528\u3002<\/p>\n<h3 id=\"2-%e5%a4%9a%e8%a1%8c%e5%ad%90%e6%9f%a5%e8%a9%a2%e7%af%84%e4%be%8b-GaWLomavxI\">2. \u591a\u884c\u5b50\u67e5\u8a62\u7bc4\u4f8b<\/h3>\n<pre><code>SELECT ProductName\nFROM Products\nWHERE CategoryID IN (SELECT CategoryID FROM Categories WHERE CategoryName = 'Beverages');<\/code><\/pre>\n<p>\u9019\u500b\u67e5\u8a62\u8fd4\u56de\u6240\u6709\u5c6c\u65bc\u201cBeverages\u201d\u985e\u5225\u7684\u7522\u54c1\u540d\u7a31\u3002\u5167\u90e8\u7684\u5b50\u67e5\u8a62\u8fd4\u56de\u6240\u6709\u201cBeverages\u201d\u985e\u5225\u7684 CategoryID\uff0c\u5916\u90e8\u67e5\u8a62\u5247\u6839\u64da\u9019\u4e9b ID \u6aa2\u7d22\u7522\u54c1\u3002<\/p>\n<h3 id=\"3-%e7%9b%b8%e9%97%9c%e5%ad%90%e6%9f%a5%e8%a9%a2%e7%af%84%e4%be%8b-GaWLomavxI\">3. \u76f8\u95dc\u5b50\u67e5\u8a62\u7bc4\u4f8b<\/h3>\n<pre><code>SELECT e1.FirstName, e1.LastName\nFROM Employees e1\nWHERE e1.Salary &gt; (SELECT AVG(e2.Salary) FROM Employees e2 WHERE e1.DepartmentID = e2.DepartmentID);<\/code><\/pre>\n<p>\u5728\u9019\u500b\u7bc4\u4f8b\u4e2d\uff0c\u67e5\u8a62\u8fd4\u56de\u6bcf\u500b\u90e8\u9580\u4e2d\u85aa\u6c34\u9ad8\u65bc\u8a72\u90e8\u9580\u5e73\u5747\u85aa\u6c34\u7684\u54e1\u5de5\u3002\u9019\u88e1\u7684\u5b50\u67e5\u8a62\u4f9d\u8cf4\u65bc\u5916\u90e8\u67e5\u8a62\u7684 DepartmentID\u3002<\/p>\n<h2 id=\"%e5%ad%90%e6%9f%a5%e8%a9%a2%e7%9a%84%e6%80%a7%e8%83%bd%e8%80%83%e9%87%8f-GaWLomavxI\">\u5b50\u67e5\u8a62\u7684\u6027\u80fd\u8003\u91cf<\/h2>\n<p>\u96d6\u7136\u5b50\u67e5\u8a62\u63d0\u4f9b\u4e86\u9748\u6d3b\u6027\uff0c\u4f46\u5728\u67d0\u4e9b\u60c5\u6cc1\u4e0b\u53ef\u80fd\u6703\u5f71\u97ff\u67e5\u8a62\u6027\u80fd\u3002\u7279\u5225\u662f\u7576\u5b50\u67e5\u8a62\u8fd4\u56de\u5927\u91cf\u8cc7\u6599\u6642\uff0c\u53ef\u80fd\u6703\u5c0e\u81f4\u67e5\u8a62\u57f7\u884c\u901f\u5ea6\u8b8a\u6162\u3002\u56e0\u6b64\uff0c\u5728\u8a2d\u8a08\u67e5\u8a62\u6642\uff0c\u958b\u767c\u8005\u61c9\u8003\u616e\u4f7f\u7528 JOIN \u6216\u5176\u4ed6\u65b9\u6cd5\u4f86\u512a\u5316\u6027\u80fd\u3002<\/p>\n<h2 id=\"%e7%b8%bd%e7%b5%90-GaWLomavxI\">\u7e3d\u7d50<\/h2>\n<p>\u5b50\u67e5\u8a62\u662f T-SQL \u4e2d\u4e00\u500b\u5f37\u5927\u7684\u5de5\u5177\uff0c\u80fd\u5920\u5e6b\u52a9\u958b\u767c\u8005\u9032\u884c\u8907\u96dc\u7684\u8cc7\u6599\u6aa2\u7d22\u3002\u901a\u904e\u7406\u89e3\u5b50\u67e5\u8a62\u7684\u985e\u578b\u53ca\u5176\u4f7f\u7528\u65b9\u6cd5\uff0c\u958b\u767c\u8005\u53ef\u4ee5\u66f4\u6709\u6548\u5730\u64b0\u5beb\u67e5\u8a62\uff0c\u5f9e\u800c\u63d0\u9ad8\u8cc7\u6599\u5eab\u64cd\u4f5c\u7684\u6548\u7387\u3002\u5c0d\u65bc\u9700\u8981\u9ad8\u6548\u80fd\u7684\u61c9\u7528\uff0c\u9078\u64c7\u5408\u9069\u7684 <a href=\"https:\/\/server.hk\">VPS<\/a> \u89e3\u6c7a\u65b9\u6848\u4e5f\u662f\u81f3\u95dc\u91cd\u8981\u7684\uff0c\u9019\u6a23\u53ef\u4ee5\u78ba\u4fdd\u8cc7\u6599\u5eab\u7684\u7a69\u5b9a\u6027\u548c\u5feb\u901f\u97ff\u61c9\u3002<\/p>\n","protected":false},"excerpt":{"rendered":"<p>\u6df1\u5165\u7406\u89e3T-SQL\u4e2d\u7684\u5b50\u67e5\u8a62\uff0c\u638c\u63e1\u67e5\u8a62\u9032\u968e\u6280\u5de7\uff0c\u63d0\u5347\u6578\u64da\u8655\u7406\u6548\u7387\u8207\u67e5\u8a62\u6027\u80fd\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-168823","post","type-post","status-publish","format-standard","hentry","category-database"],"_links":{"self":[{"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/posts\/168823","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=168823"}],"version-history":[{"count":1,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/posts\/168823\/revisions"}],"predecessor-version":[{"id":168824,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/posts\/168823\/revisions\/168824"}],"wp:attachment":[{"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/media?parent=168823"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/categories?post=168823"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/tags?post=168823"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}