{"id":183534,"date":"2024-11-10T05:37:17","date_gmt":"2024-11-09T21:37:17","guid":{"rendered":"https:\/\/server.hk\/cnblog\/183534\/"},"modified":"2024-11-10T05:37:18","modified_gmt":"2024-11-09T21:37:18","slug":"%e4%bd%bf%e7%94%a8-mssql-%e5%ae%8c%e6%88%90%e7%a9%ba%e5%80%bc%e6%9f%a5%e8%a9%a2%ef%bc%88mssql-%e7%ad%89%e6%96%bc%e7%a9%ba%ef%bc%89","status":"publish","type":"post","link":"https:\/\/server.hk\/cnblog\/183534\/","title":{"rendered":"\u4f7f\u7528 MSSQL \u5b8c\u6210\u7a7a\u503c\u67e5\u8a62\uff08mssql \u7b49\u65bc\u7a7a\uff09"},"content":{"rendered":"<h1 id=\"%e4%bd%bf%e7%94%a8-mssql-%e5%ae%8c%e6%88%90%e7%a9%ba%e5%80%bc%e6%9f%a5%e8%a9%a2%ef%bc%88mssql-%e7%ad%89%e6%96%bc%e7%a9%ba%ef%bc%89-oYmyTJavMA\">\u4f7f\u7528 MSSQL \u5b8c\u6210\u7a7a\u503c\u67e5\u8a62\uff08mssql \u7b49\u65bc\u7a7a\uff09<\/h1>\n<p>\u5728\u8cc7\u6599\u5eab\u7ba1\u7406\u4e2d\uff0c\u67e5\u8a62\u7a7a\u503c\u662f\u4e00\u500b\u5e38\u898b\u7684\u9700\u6c42\u3002\u5c0d\u65bc\u4f7f\u7528 Microsoft SQL Server\uff08MSSQL\uff09\u7684\u958b\u767c\u8005\u4f86\u8aaa\uff0c\u4e86\u89e3\u5982\u4f55\u6709\u6548\u5730\u67e5\u8a62\u7a7a\u503c\uff08NULL\uff09\u662f\u975e\u5e38\u91cd\u8981\u7684\u3002\u672c\u6587\u5c07\u6df1\u5165\u63a2\u8a0e\u5982\u4f55\u5728 MSSQL \u4e2d\u9032\u884c\u7a7a\u503c\u67e5\u8a62\uff0c\u4e26\u63d0\u4f9b\u76f8\u95dc\u7684\u7bc4\u4f8b\u548c\u6700\u4f73\u5be6\u8e10\u3002<\/p>\n<h2 id=\"%e4%bb%80%e9%ba%bc%e6%98%af%e7%a9%ba%e5%80%bc%ef%bc%88null%ef%bc%89%ef%bc%9f-oYmyTJavMA\">\u4ec0\u9ebc\u662f\u7a7a\u503c\uff08NULL\uff09\uff1f<\/h2>\n<p>\u5728 SQL \u4e2d\uff0c\u7a7a\u503c\uff08NULL\uff09\u8868\u793a\u7f3a\u5931\u6216\u672a\u77e5\u7684\u6578\u64da\u3002\u9019\u8207\u7a7a\u5b57\u7b26\u4e32\u6216\u96f6\u4e0d\u540c\uff0c\u56e0\u70ba\u7a7a\u503c\u8868\u793a\u8a72\u5b57\u6bb5\u6c92\u6709\u4efb\u4f55\u6578\u64da\u3002\u7576\u6211\u5011\u5728\u8cc7\u6599\u5eab\u4e2d\u9032\u884c\u67e5\u8a62\u6642\uff0c\u5fc5\u9808\u7279\u5225\u6ce8\u610f\u5982\u4f55\u8655\u7406\u9019\u4e9b\u7a7a\u503c\uff0c\u4ee5\u78ba\u4fdd\u67e5\u8a62\u7684\u6e96\u78ba\u6027\u3002<\/p>\n<h2 id=\"%e5%a6%82%e4%bd%95%e6%9f%a5%e8%a9%a2%e7%a9%ba%e5%80%bc-oYmyTJavMA\">\u5982\u4f55\u67e5\u8a62\u7a7a\u503c<\/h2>\n<p>\u5728 MSSQL \u4e2d\uff0c\u67e5\u8a62\u7a7a\u503c\u901a\u5e38\u4f7f\u7528 IS NULL \u6216 IS NOT NULL \u689d\u4ef6\u3002\u4ee5\u4e0b\u662f\u4e00\u4e9b\u57fa\u672c\u7684\u67e5\u8a62\u7bc4\u4f8b\uff1a<\/p>\n<h3 id=\"%e6%9f%a5%e8%a9%a2%e7%a9%ba%e5%80%bc-oYmyTJavMA\">\u67e5\u8a62\u7a7a\u503c<\/h3>\n<pre><code>SELECT * FROM \u8868\u540d WHERE \u6b04\u4f4d\u540d IS NULL;<\/code><\/pre>\n<p>\u9019\u689d\u67e5\u8a62\u5c07\u8fd4\u56de\u6240\u6709\u5728\u6307\u5b9a\u6b04\u4f4d\u4e2d\u70ba\u7a7a\u503c\u7684\u8a18\u9304\u3002<\/p>\n<h3 id=\"%e6%9f%a5%e8%a9%a2%e9%9d%9e%e7%a9%ba%e5%80%bc-oYmyTJavMA\">\u67e5\u8a62\u975e\u7a7a\u503c<\/h3>\n<pre><code>SELECT * FROM \u8868\u540d WHERE \u6b04\u4f4d\u540d IS NOT NULL;<\/code><\/pre>\n<p>\u9019\u689d\u67e5\u8a62\u5c07\u8fd4\u56de\u6240\u6709\u5728\u6307\u5b9a\u6b04\u4f4d\u4e2d\u4e0d\u70ba\u7a7a\u503c\u7684\u8a18\u9304\u3002<\/p>\n<h2 id=\"%e4%bd%bf%e7%94%a8%e7%a9%ba%e5%80%bc%e7%9a%84%e6%b3%a8%e6%84%8f%e4%ba%8b%e9%a0%85-oYmyTJavMA\">\u4f7f\u7528\u7a7a\u503c\u7684\u6ce8\u610f\u4e8b\u9805<\/h2>\n<p>\u5728\u9032\u884c\u7a7a\u503c\u67e5\u8a62\u6642\uff0c\u6709\u5e7e\u500b\u6ce8\u610f\u4e8b\u9805\u9700\u8981\u8003\u616e\uff1a<\/p>\n<ul>\n<li><strong>\u7a7a\u503c\u8207\u6bd4\u8f03\u904b\u7b97\u7b26\uff1a<\/strong>\u5728 SQL \u4e2d\uff0c\u7a7a\u503c\u7121\u6cd5\u8207\u5176\u4ed6\u503c\u9032\u884c\u6bd4\u8f03\u3002\u56e0\u6b64\uff0c\u4f7f\u7528\u7b49\u65bc\uff08=\uff09\u6216\u4e0d\u7b49\u65bc\uff08\uff09\u904b\u7b97\u7b26\u4f86\u67e5\u8a62\u7a7a\u503c\u662f\u7121\u6548\u7684\u3002<\/li>\n<li><strong>\u805a\u5408\u51fd\u6578\u7684\u5f71\u97ff\uff1a<\/strong>\u67d0\u4e9b\u805a\u5408\u51fd\u6578\uff08\u5982 COUNT\uff09\u5728\u8a08\u7b97\u6642\u6703\u5ffd\u7565\u7a7a\u503c\u3002\u9019\u610f\u5473\u8457\u5982\u679c\u4f60\u5728\u8a08\u7b97\u7e3d\u6578\u6642\uff0c\u7a7a\u503c\u4e0d\u6703\u88ab\u8a08\u5165\u3002<\/li>\n<li><strong>\u7d22\u5f15\u7684\u5f71\u97ff\uff1a<\/strong>\u5728\u67d0\u4e9b\u60c5\u6cc1\u4e0b\uff0c\u7a7a\u503c\u53ef\u80fd\u6703\u5f71\u97ff\u7d22\u5f15\u7684\u6027\u80fd\u3002\u4e86\u89e3\u5982\u4f55\u8a2d\u8a08\u7d22\u5f15\u4ee5\u512a\u5316\u67e5\u8a62\u6027\u80fd\u662f\u975e\u5e38\u91cd\u8981\u7684\u3002<\/li>\n<\/ul>\n<h2 id=\"%e7%af%84%e4%be%8b%ef%bc%9a%e6%9f%a5%e8%a9%a2%e7%a9%ba%e5%80%bc%e7%9a%84%e5%af%a6%e9%9a%9b%e6%87%89%e7%94%a8-oYmyTJavMA\">\u7bc4\u4f8b\uff1a\u67e5\u8a62\u7a7a\u503c\u7684\u5be6\u969b\u61c9\u7528<\/h2>\n<p>\u5047\u8a2d\u6211\u5011\u6709\u4e00\u500b\u540d\u70ba <code>Customers<\/code> \u7684\u8868\u683c\uff0c\u5176\u4e2d\u5305\u542b\u5ba2\u6236\u7684\u8cc7\u6599\uff0c\u5305\u62ec <code>CustomerID<\/code>\u3001<code>Name<\/code> \u548c <code>Email<\/code> \u6b04\u4f4d\u3002\u6211\u5011\u5e0c\u671b\u67e5\u8a62\u6240\u6709\u6c92\u6709\u63d0\u4f9b\u96fb\u5b50\u90f5\u4ef6\u5730\u5740\u7684\u5ba2\u6236\u3002<\/p>\n<pre><code>SELECT * FROM Customers WHERE Email IS NULL;<\/code><\/pre>\n<p>\u9019\u689d\u67e5\u8a62\u5c07\u8fd4\u56de\u6240\u6709 <code>Email<\/code> \u6b04\u4f4d\u70ba\u7a7a\u7684\u5ba2\u6236\u8a18\u9304\u3002<\/p>\n<h2 id=\"%e7%b5%90%e8%ab%96-oYmyTJavMA\">\u7d50\u8ad6<\/h2>\n<p>\u5728 MSSQL \u4e2d\u67e5\u8a62\u7a7a\u503c\u662f\u4e00\u500b\u57fa\u672c\u4f46\u91cd\u8981\u7684\u6280\u80fd\u3002\u901a\u904e\u4f7f\u7528 <code>IS NULL<\/code> \u548c <code>IS NOT NULL<\/code> \u689d\u4ef6\uff0c\u958b\u767c\u8005\u53ef\u4ee5\u6709\u6548\u5730\u7be9\u9078\u51fa\u6240\u9700\u7684\u6578\u64da\u3002\u4e86\u89e3\u7a7a\u503c\u7684\u7279\u6027\u53ca\u5176\u5728\u67e5\u8a62\u4e2d\u7684\u5f71\u97ff\uff0c\u5c07\u6709\u52a9\u65bc\u63d0\u9ad8\u8cc7\u6599\u5eab\u64cd\u4f5c\u7684\u6e96\u78ba\u6027\u548c\u6548\u7387\u3002<\/p>\n<p>\u5982\u679c\u60a8\u6b63\u5728\u5c0b\u627e\u9ad8\u6548\u7684 <a href=\"https:\/\/server.hk\">\u9999\u6e2fVPS<\/a> \u89e3\u6c7a\u65b9\u6848\uff0cServer.HK \u63d0\u4f9b\u591a\u7a2e\u9078\u64c7\uff0c\u6eff\u8db3\u4e0d\u540c\u9700\u6c42\u7684\u5ba2\u6236\u3002\u7121\u8ad6\u662f\u8cc7\u6599\u5eab\u7ba1\u7406\u9084\u662f\u7db2\u7ad9\u6258\u7ba1\uff0c\u6211\u5011\u7684 <a href=\"https:\/\/server.hk\">\u4f3a\u670d\u5668<\/a> \u90fd\u80fd\u70ba\u60a8\u63d0\u4f9b\u7a69\u5b9a\u7684\u652f\u6301\u3002<\/p>\n","protected":false},"excerpt":{"rendered":"<p>\u4f7f\u7528 MSSQL 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