{"id":138403,"date":"2024-10-31T14:11:22","date_gmt":"2024-10-31T06:11:22","guid":{"rendered":"https:\/\/server.hk\/cnblog\/138403\/"},"modified":"2024-10-31T14:11:23","modified_gmt":"2024-10-31T06:11:23","slug":"sql-server%e8%a1%a8%e5%88%86%e5%8d%80%e7%9a%84null%e5%80%bc%e5%95%8f%e9%a1%8c","status":"publish","type":"post","link":"https:\/\/server.hk\/cnblog\/138403\/","title":{"rendered":"SQL Server\u8868\u5206\u5340\u7684NULL\u503c\u554f\u984c"},"content":{"rendered":"<h1 id=\"sql-server%e8%a1%a8%e5%88%86%e5%8d%80%e7%9a%84null%e5%80%bc%e5%95%8f%e9%a1%8c-cIxnqHzwep\">SQL Server\u8868\u5206\u5340\u7684NULL\u503c\u554f\u984c<\/h1>\n<p>\u5728\u6578\u64da\u5eab\u7ba1\u7406\u4e2d\uff0c\u8868\u5206\u5340\u662f\u4e00\u7a2e\u5e38\u898b\u7684\u6280\u8853\uff0c\u65e8\u5728\u63d0\u9ad8\u67e5\u8a62\u6027\u80fd\u548c\u6578\u64da\u7ba1\u7406\u7684\u9748\u6d3b\u6027\u3002SQL Server\u63d0\u4f9b\u4e86\u5f37\u5927\u7684\u5206\u5340\u529f\u80fd\uff0c\u5141\u8a31\u7528\u6236\u6839\u64da\u7279\u5b9a\u7684\u5217\u5c07\u6578\u64da\u5206\u6563\u5230\u4e0d\u540c\u7684\u5206\u5340\u4e2d\u3002\u7136\u800c\uff0c\u5728\u5be6\u969b\u61c9\u7528\u4e2d\uff0cNULL\u503c\u7684\u8655\u7406\u5e38\u5e38\u6210\u70ba\u4e00\u500b\u68d8\u624b\u7684\u554f\u984c\u3002\u672c\u6587\u5c07\u6df1\u5165\u63a2\u8a0eSQL Server\u8868\u5206\u5340\u4e2d\u7684NULL\u503c\u554f\u984c\uff0c\u4e26\u63d0\u4f9b\u4e00\u4e9b\u89e3\u6c7a\u65b9\u6848\u548c\u6700\u4f73\u5be6\u8e10\u3002<\/p>\n<h2 id=\"%e4%bb%80%e9%ba%bc%e6%98%af%e8%a1%a8%e5%88%86%e5%8d%80%ef%bc%9f-cIxnqHzwep\">\u4ec0\u9ebc\u662f\u8868\u5206\u5340\uff1f<\/h2>\n<p>\u8868\u5206\u5340\u662f\u5c07\u4e00\u500b\u5927\u578b\u8868\u5283\u5206\u70ba\u591a\u500b\u8f03\u5c0f\u7684\u3001\u53ef\u7ba1\u7406\u7684\u90e8\u5206\uff08\u5373\u5206\u5340\uff09\uff0c\u6bcf\u500b\u5206\u5340\u53ef\u4ee5\u7368\u7acb\u5b58\u5132\u548c\u67e5\u8a62\u3002\u9019\u6a23\u7684\u8a2d\u8a08\u4e0d\u50c5\u80fd\u63d0\u9ad8\u67e5\u8a62\u6027\u80fd\uff0c\u9084\u80fd\u7c21\u5316\u6578\u64da\u7684\u7dad\u8b77\u548c\u7ba1\u7406\u3002SQL Server\u652f\u6301\u591a\u7a2e\u5206\u5340\u985e\u578b\uff0c\u5305\u62ec\u7bc4\u570d\u5206\u5340\u3001\u5217\u8868\u5206\u5340\u548c\u54c8\u5e0c\u5206\u5340\u7b49\u3002<\/p>\n<h2 id=\"null%e5%80%bc%e5%9c%a8%e5%88%86%e5%8d%80%e4%b8%ad%e7%9a%84%e6%8c%91%e6%88%b0-cIxnqHzwep\">NULL\u503c\u5728\u5206\u5340\u4e2d\u7684\u6311\u6230<\/h2>\n<p>\u5728SQL Server\u4e2d\uff0cNULL\u503c\u7684\u5b58\u5728\u53ef\u80fd\u6703\u5c0d\u5206\u5340\u7684\u8a2d\u8a08\u548c\u6027\u80fd\u7522\u751f\u5f71\u97ff\u3002\u7576\u4f7f\u7528\u67d0\u500b\u5217\u4f5c\u70ba\u5206\u5340\u9375\u6642\uff0cNULL\u503c\u7684\u8655\u7406\u65b9\u5f0f\u9700\u8981\u7279\u5225\u6ce8\u610f\u3002\u4ee5\u4e0b\u662f\u4e00\u4e9b\u4e3b\u8981\u6311\u6230\uff1a<\/p>\n<ul>\n<li><strong>\u5206\u5340\u9375\u7684\u9078\u64c7\uff1a<\/strong>\u5982\u679c\u5206\u5340\u9375\u7684\u5217\u5305\u542bNULL\u503c\uff0c\u9019\u4e9bNULL\u503c\u5c07\u7121\u6cd5\u88ab\u6b63\u78ba\u5730\u5206\u914d\u5230\u4efb\u4f55\u4e00\u500b\u5206\u5340\u4e2d\u3002\u9019\u53ef\u80fd\u5c0e\u81f4\u6578\u64da\u4e0d\u5747\u52fb\u5206\u4f48\uff0c\u5f71\u97ff\u67e5\u8a62\u6027\u80fd\u3002<\/li>\n<li><strong>\u67e5\u8a62\u6027\u80fd\uff1a<\/strong>\u5728\u67e5\u8a62\u6642\uff0c\u5982\u679c\u5206\u5340\u9375\u7684\u5217\u5305\u542bNULL\u503c\uff0cSQL Server\u53ef\u80fd\u7121\u6cd5\u6709\u6548\u5229\u7528\u5206\u5340\uff0c\u5f9e\u800c\u5c0e\u81f4\u5168\u8868\u6383\u63cf\uff0c\u5f71\u97ff\u67e5\u8a62\u6548\u7387\u3002<\/li>\n<li><strong>\u6578\u64da\u5b8c\u6574\u6027\uff1a<\/strong>\u5728\u67d0\u4e9b\u60c5\u6cc1\u4e0b\uff0cNULL\u503c\u53ef\u80fd\u6703\u5c0e\u81f4\u6578\u64da\u5b8c\u6574\u6027\u554f\u984c\uff0c\u7279\u5225\u662f\u5728\u9700\u8981\u9032\u884c\u6578\u64da\u805a\u5408\u6216\u8a08\u7b97\u7684\u60c5\u6cc1\u4e0b\u3002<\/li>\n<\/ul>\n<h2 id=\"%e8%a7%a3%e6%b1%ba%e6%96%b9%e6%a1%88-cIxnqHzwep\">\u89e3\u6c7a\u65b9\u6848<\/h2>\n<p>\u70ba\u4e86\u6709\u6548\u5730\u8655\u7406SQL Server\u8868\u5206\u5340\u4e2d\u7684NULL\u503c\u554f\u984c\uff0c\u53ef\u4ee5\u8003\u616e\u4ee5\u4e0b\u5e7e\u7a2e\u89e3\u6c7a\u65b9\u6848\uff1a<\/p>\n<h3 id=\"1-%e9%81%b8%e6%93%87%e5%90%88%e9%81%a9%e7%9a%84%e5%88%86%e5%8d%80%e9%8d%b5-cIxnqHzwep\">1. \u9078\u64c7\u5408\u9069\u7684\u5206\u5340\u9375<\/h3>\n<p>\u5728\u8a2d\u8a08\u5206\u5340\u6642\uff0c\u61c9\u9078\u64c7\u4e0d\u5305\u542bNULL\u503c\u7684\u5217\u4f5c\u70ba\u5206\u5340\u9375\u3002\u5982\u679c\u5fc5\u9808\u4f7f\u7528\u53ef\u80fd\u5305\u542bNULL\u503c\u7684\u5217\uff0c\u5247\u53ef\u4ee5\u8003\u616e\u4f7f\u7528\u5176\u4ed6\u5217\u4f5c\u70ba\u8f14\u52a9\u5206\u5340\u9375\u3002<\/p>\n<h3 id=\"2-%e4%bd%bf%e7%94%a8%e9%bb%98%e8%aa%8d%e5%80%bc-cIxnqHzwep\">2. \u4f7f\u7528\u9ed8\u8a8d\u503c<\/h3>\n<p>\u5728\u63d2\u5165\u6578\u64da\u6642\uff0c\u53ef\u4ee5\u8003\u616e\u4f7f\u7528\u9ed8\u8a8d\u503c\u4f86\u66ff\u4ee3NULL\u503c\u3002\u9019\u6a23\u53ef\u4ee5\u78ba\u4fdd\u6240\u6709\u6578\u64da\u90fd\u6709\u6709\u6548\u7684\u5206\u5340\u9375\uff0c\u5f9e\u800c\u907f\u514dNULL\u503c\u5e36\u4f86\u7684\u554f\u984c\u3002<\/p>\n<pre><code>INSERT INTO YourTable (PartitionKey, OtherColumn)\nVALUES (ISNULL(@YourValue, 'DefaultValue'), @OtherValue);\n<\/code><\/pre>\n<h3 id=\"3-%e5%ae%9a%e6%9c%9f%e6%b8%85%e7%90%86null%e5%80%bc-cIxnqHzwep\">3. \u5b9a\u671f\u6e05\u7406NULL\u503c<\/h3>\n<p>\u5b9a\u671f\u6aa2\u67e5\u548c\u6e05\u7406\u8868\u4e2d\u7684NULL\u503c\uff0c\u53ef\u4ee5\u5e6b\u52a9\u4fdd\u6301\u6578\u64da\u7684\u6574\u6f54\u6027\u548c\u67e5\u8a62\u6027\u80fd\u3002\u53ef\u4ee5\u4f7f\u7528SQL Server\u7684\u5b9a\u671f\u7dad\u8b77\u8a08\u5283\u4f86\u81ea\u52d5\u57f7\u884c\u9019\u4e9b\u64cd\u4f5c\u3002<\/p>\n<h2 id=\"%e6%9c%80%e4%bd%b3%e5%af%a6%e8%b8%90-cIxnqHzwep\">\u6700\u4f73\u5be6\u8e10<\/h2>\n<p>\u5728\u8655\u7406SQL Server\u8868\u5206\u5340\u7684NULL\u503c\u554f\u984c\u6642\uff0c\u9075\u5faa\u4e00\u4e9b\u6700\u4f73\u5be6\u8e10\u53ef\u4ee5\u5e6b\u52a9\u63d0\u9ad8\u7cfb\u7d71\u7684\u7a69\u5b9a\u6027\u548c\u6027\u80fd\uff1a<\/p>\n<ul>\n<li>\u5728\u8a2d\u8a08\u6578\u64da\u6a21\u578b\u6642\uff0c\u76e1\u91cf\u907f\u514d\u4f7f\u7528NULL\u503c\uff0c\u7279\u5225\u662f\u5728\u5206\u5340\u9375\u4e0a\u3002<\/li>\n<li>\u5b9a\u671f\u76e3\u63a7\u548c\u5206\u6790\u67e5\u8a62\u6027\u80fd\uff0c\u53ca\u6642\u8abf\u6574\u5206\u5340\u7b56\u7565\u3002<\/li>\n<li>\u4f7f\u7528SQL Server\u7684\u6027\u80fd\u76e3\u63a7\u5de5\u5177\uff0c\u6aa2\u67e5\u5206\u5340\u7684\u4f7f\u7528\u60c5\u6cc1\u548c\u6578\u64da\u5206\u4f48\u3002<\/li>\n<\/ul>\n<h2 id=\"%e7%b8%bd%e7%b5%90-cIxnqHzwep\">\u7e3d\u7d50<\/h2>\n<p>\u5728SQL Server\u4e2d\uff0c\u8868\u5206\u5340\u662f\u4e00\u7a2e\u6709\u6548\u7684\u6578\u64da\u7ba1\u7406\u6280\u8853\uff0c\u4f46NULL\u503c\u7684\u5b58\u5728\u53ef\u80fd\u6703\u5c0d\u5176\u6027\u80fd\u548c\u7a69\u5b9a\u6027\u9020\u6210\u5f71\u97ff\u3002\u901a\u904e\u9078\u64c7\u5408\u9069\u7684\u5206\u5340\u9375\u3001\u4f7f\u7528\u9ed8\u8a8d\u503c\u4ee5\u53ca\u5b9a\u671f\u6e05\u7406NULL\u503c\uff0c\u53ef\u4ee5\u6709\u6548\u5730\u89e3\u6c7a\u9019\u4e9b\u554f\u984c\u3002\u5c0d\u65bc\u9700\u8981\u9ad8\u6548\u6578\u64da\u8655\u7406\u7684\u4f01\u696d\u4f86\u8aaa\uff0c\u4e86\u89e3\u548c\u61c9\u5c0d\u9019\u4e9b\u6311\u6230\u662f\u81f3\u95dc\u91cd\u8981\u7684\u3002\u5982\u679c\u60a8\u6b63\u5728\u5c0b\u627e\u53ef\u9760\u7684 <a href=\"https:\/\/server.hk\">\u9999\u6e2fVPS<\/a> \u89e3\u6c7a\u65b9\u6848\uff0cServer.HK\u63d0\u4f9b\u591a\u7a2e\u9078\u64c7\u4ee5\u6eff\u8db3\u60a8\u7684\u9700\u6c42\u3002<\/p>\n","protected":false},"excerpt":{"rendered":"<p>\u63a2\u8ba8SQL Server\u8868\u5206\u533a\u4e2dNULL\u503c\u7684\u5904\u7406\u95ee\u9898\uff0c\u5206\u6790\u5176\u5bf9\u67e5\u8be2\u6027\u80fd\u548c\u6570\u636e\u7ba1\u7406\u7684\u5f71\u54cd\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-138403","post","type-post","status-publish","format-standard","hentry","category-database"],"_links":{"self":[{"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/posts\/138403","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=138403"}],"version-history":[{"count":1,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/posts\/138403\/revisions"}],"predecessor-version":[{"id":138404,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/posts\/138403\/revisions\/138404"}],"wp:attachment":[{"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/media?parent=138403"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/categories?post=138403"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/tags?post=138403"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}