{"id":143693,"date":"2024-11-01T00:15:22","date_gmt":"2024-10-31T16:15:22","guid":{"rendered":"https:\/\/server.hk\/cnblog\/143693\/"},"modified":"2024-11-01T00:15:23","modified_gmt":"2024-10-31T16:15:23","slug":"sql-server%ef%bc%9a%e8%99%95%e7%90%86%e9%9d%9e%e6%95%b4%e6%95%b8%e7%9a%84%e6%96%b0%e6%96%b9%e6%b3%95%ef%bc%88sqlserver-%e9%9d%9e%e6%95%b4%e6%95%b8%ef%bc%89","status":"publish","type":"post","link":"https:\/\/server.hk\/cnblog\/143693\/","title":{"rendered":"SQL Server\uff1a\u8655\u7406\u975e\u6574\u6578\u7684\u65b0\u65b9\u6cd5\uff08sqlserver \u975e\u6574\u6578\uff09"},"content":{"rendered":"<h1 id=\"sql-server%ef%bc%9a%e8%99%95%e7%90%86%e9%9d%9e%e6%95%b4%e6%95%b8%e7%9a%84%e6%96%b0%e6%96%b9%e6%b3%95%ef%bc%88sqlserver-%e9%9d%9e%e6%95%b4%e6%95%b8%ef%bc%89-cIlAxsljyP\">SQL Server\uff1a\u8655\u7406\u975e\u6574\u6578\u7684\u65b0\u65b9\u6cd5\uff08sqlserver \u975e\u6574\u6578\uff09<\/h1>\n<p>\u5728\u7576\u4eca\u7684\u6578\u64da\u9a45\u52d5\u4e16\u754c\u4e2d\uff0cSQL Server \u4f5c\u70ba\u4e00\u500b\u5f37\u5927\u7684\u6578\u64da\u5eab\u7ba1\u7406\u7cfb\u7d71\uff0c\u5df2\u7d93\u6210\u70ba\u8a31\u591a\u4f01\u696d\u7684\u9996\u9078\u3002\u96a8\u8457\u6578\u64da\u985e\u578b\u7684\u591a\u6a23\u5316\uff0c\u8655\u7406\u975e\u6574\u6578\u6578\u64da\u7684\u9700\u6c42\u65e5\u76ca\u589e\u52a0\u3002\u672c\u6587\u5c07\u63a2\u8a0e SQL Server \u4e2d\u8655\u7406\u975e\u6574\u6578\u6578\u64da\u7684\u65b0\u65b9\u6cd5\uff0c\u4e26\u63d0\u4f9b\u4e00\u4e9b\u5be6\u7528\u7684\u793a\u4f8b\u548c\u4ee3\u78bc\u7247\u6bb5\u3002<\/p>\n<h2 id=\"%e9%9d%9e%e6%95%b4%e6%95%b8%e6%95%b8%e6%93%9a%e9%a1%9e%e5%9e%8b%e6%a6%82%e8%bf%b0-cIlAxsljyP\">\u975e\u6574\u6578\u6578\u64da\u985e\u578b\u6982\u8ff0<\/h2>\n<p>\u5728 SQL Server \u4e2d\uff0c\u9664\u4e86\u6574\u6578\u985e\u578b\uff08\u5982 INT\u3001BIGINT\uff09\u5916\uff0c\u9084\u6709\u591a\u7a2e\u975e\u6574\u6578\u6578\u64da\u985e\u578b\uff0c\u5305\u62ec\uff1a<\/p>\n<ul>\n<li><strong>\u6d6e\u9ede\u6578\uff08FLOAT\u3001REAL\uff09<\/strong>\uff1a\u7528\u65bc\u5b58\u5132\u5e36\u6709\u5c0f\u6578\u7684\u6578\u5b57\u3002<\/li>\n<li><strong>\u5341\u9032\u5236\uff08DECIMAL\u3001NUMERIC\uff09<\/strong>\uff1a\u63d0\u4f9b\u7cbe\u78ba\u7684\u6578\u5b57\u5b58\u5132\uff0c\u9069\u5408\u91d1\u878d\u8a08\u7b97\u3002<\/li>\n<li><strong>\u5b57\u4e32\uff08CHAR\u3001VARCHAR\u3001NCHAR\u3001NVARCHAR\uff09<\/strong>\uff1a\u7528\u65bc\u5b58\u5132\u6587\u672c\u6578\u64da\u3002<\/li>\n<li><strong>\u65e5\u671f\u548c\u6642\u9593\uff08DATE\u3001TIME\u3001DATETIME\uff09<\/strong>\uff1a\u7528\u65bc\u5b58\u5132\u65e5\u671f\u548c\u6642\u9593\u4fe1\u606f\u3002<\/li>\n<\/ul>\n<h2 id=\"%e8%99%95%e7%90%86%e9%9d%9e%e6%95%b4%e6%95%b8%e6%95%b8%e6%93%9a%e7%9a%84%e6%8c%91%e6%88%b0-cIlAxsljyP\">\u8655\u7406\u975e\u6574\u6578\u6578\u64da\u7684\u6311\u6230<\/h2>\n<p>\u5728 SQL Server \u4e2d\u8655\u7406\u975e\u6574\u6578\u6578\u64da\u6642\uff0c\u958b\u767c\u8005\u53ef\u80fd\u6703\u9762\u81e8\u4e00\u4e9b\u6311\u6230\uff0c\u4f8b\u5982\uff1a<\/p>\n<ul>\n<li>\u6578\u64da\u985e\u578b\u8f49\u63db\uff1a\u5728\u9032\u884c\u8a08\u7b97\u6216\u6bd4\u8f03\u6642\uff0c\u53ef\u80fd\u9700\u8981\u5c07\u6578\u64da\u985e\u578b\u9032\u884c\u8f49\u63db\u3002<\/li>\n<li>\u7cbe\u5ea6\u554f\u984c\uff1a\u6d6e\u9ede\u6578\u5728\u8a08\u7b97\u904e\u7a0b\u4e2d\u53ef\u80fd\u6703\u51fa\u73fe\u7cbe\u5ea6\u640d\u5931\u3002<\/li>\n<li>\u6027\u80fd\u554f\u984c\uff1a\u8655\u7406\u5927\u91cf\u975e\u6574\u6578\u6578\u64da\u6642\uff0c\u67e5\u8a62\u6027\u80fd\u53ef\u80fd\u6703\u53d7\u5230\u5f71\u97ff\u3002<\/li>\n<\/ul>\n<h2 id=\"%e6%96%b0%e6%96%b9%e6%b3%95%ef%bc%9a%e4%bd%bf%e7%94%a8%e8%a1%a8%e9%81%94%e5%bc%8f%e5%92%8c%e5%87%bd%e6%95%b8-cIlAxsljyP\">\u65b0\u65b9\u6cd5\uff1a\u4f7f\u7528\u8868\u9054\u5f0f\u548c\u51fd\u6578<\/h2>\n<p>\u70ba\u4e86\u6709\u6548\u5730\u8655\u7406\u975e\u6574\u6578\u6578\u64da\uff0cSQL Server \u63d0\u4f9b\u4e86\u591a\u7a2e\u8868\u9054\u5f0f\u548c\u51fd\u6578\u3002\u4ee5\u4e0b\u662f\u4e00\u4e9b\u5e38\u7528\u7684\u65b9\u6cd5\uff1a<\/p>\n<h3 id=\"1-%e4%bd%bf%e7%94%a8-cast-%e5%92%8c-convert-%e5%87%bd%e6%95%b8-cIlAxsljyP\">1. \u4f7f\u7528 CAST \u548c CONVERT \u51fd\u6578<\/h3>\n<p>\u9019\u5169\u500b\u51fd\u6578\u53ef\u4ee5\u7528\u4f86\u5c07\u4e00\u7a2e\u6578\u64da\u985e\u578b\u8f49\u63db\u70ba\u53e6\u4e00\u7a2e\u6578\u64da\u985e\u578b\u3002\u4f8b\u5982\uff1a<\/p>\n<pre><code>SELECT CAST('123.45' AS FLOAT) AS FloatValue;\nSELECT CONVERT(DECIMAL(10, 2), '123.45') AS DecimalValue;<\/code><\/pre>\n<h3 id=\"2-%e4%bd%bf%e7%94%a8-case-%e8%a1%a8%e9%81%94%e5%bc%8f-cIlAxsljyP\">2. \u4f7f\u7528 CASE \u8868\u9054\u5f0f<\/h3>\n<p>CASE \u8868\u9054\u5f0f\u53ef\u4ee5\u6839\u64da\u4e0d\u540c\u7684\u689d\u4ef6\u8fd4\u56de\u4e0d\u540c\u7684\u7d50\u679c\uff0c\u9019\u5728\u8655\u7406\u975e\u6574\u6578\u6578\u64da\u6642\u975e\u5e38\u6709\u7528\u3002\u4f8b\u5982\uff1a<\/p>\n<pre><code>SELECT \n    CASE \n        WHEN Score &gt;= 90 THEN 'A'\n        WHEN Score &gt;= 80 THEN 'B'\n        ELSE 'C'\n    END AS Grade\nFROM Students;<\/code><\/pre>\n<h3 id=\"3-%e4%bd%bf%e7%94%a8%e8%81%9a%e5%90%88%e5%87%bd%e6%95%b8-cIlAxsljyP\">3. \u4f7f\u7528\u805a\u5408\u51fd\u6578<\/h3>\n<p>\u805a\u5408\u51fd\u6578\u5982 AVG\u3001SUM\u3001COUNT \u7b49\u53ef\u4ee5\u7528\u4f86\u8a08\u7b97\u975e\u6574\u6578\u6578\u64da\u7684\u7d71\u8a08\u4fe1\u606f\u3002\u4f8b\u5982\uff1a<\/p>\n<pre><code>SELECT AVG(Salary) AS AverageSalary FROM Employees;<\/code><\/pre>\n<h2 id=\"%e6%9c%80%e4%bd%b3%e5%af%a6%e8%b8%90-cIlAxsljyP\">\u6700\u4f73\u5be6\u8e10<\/h2>\n<p>\u5728\u8655\u7406\u975e\u6574\u6578\u6578\u64da\u6642\uff0c\u9075\u5faa\u4e00\u4e9b\u6700\u4f73\u5be6\u8e10\u53ef\u4ee5\u63d0\u9ad8\u6548\u7387\u548c\u6e96\u78ba\u6027\uff1a<\/p>\n<ul>\n<li>\u9078\u64c7\u5408\u9069\u7684\u6578\u64da\u985e\u578b\uff1a\u6839\u64da\u5be6\u969b\u9700\u6c42\u9078\u64c7\u6700\u5408\u9069\u7684\u6578\u64da\u985e\u578b\uff0c\u4ee5\u6e1b\u5c11\u5b58\u5132\u7a7a\u9593\u548c\u63d0\u9ad8\u6027\u80fd\u3002<\/li>\n<li>\u907f\u514d\u4e0d\u5fc5\u8981\u7684\u985e\u578b\u8f49\u63db\uff1a\u5728\u67e5\u8a62\u4e2d\u76e1\u91cf\u907f\u514d\u983b\u7e41\u7684\u985e\u578b\u8f49\u63db\uff0c\u4ee5\u63d0\u9ad8\u67e5\u8a62\u6027\u80fd\u3002<\/li>\n<li>\u4f7f\u7528\u7d22\u5f15\uff1a\u5c0d\u65bc\u7d93\u5e38\u67e5\u8a62\u7684\u975e\u6574\u6578\u5b57\u6bb5\uff0c\u8003\u616e\u5efa\u7acb\u7d22\u5f15\u4ee5\u63d0\u9ad8\u67e5\u8a62\u901f\u5ea6\u3002<\/li>\n<\/ul>\n<h2 id=\"%e7%b8%bd%e7%b5%90-cIlAxsljyP\">\u7e3d\u7d50<\/h2>\n<p>SQL Server \u63d0\u4f9b\u4e86\u591a\u7a2e\u65b9\u6cd5\u4f86\u8655\u7406\u975e\u6574\u6578\u6578\u64da\uff0c\u5f9e\u6578\u64da\u985e\u578b\u8f49\u63db\u5230\u4f7f\u7528\u805a\u5408\u51fd\u6578\uff0c\u9019\u4e9b\u5de5\u5177\u4f7f\u5f97\u958b\u767c\u8005\u80fd\u5920\u9748\u6d3b\u5730\u8655\u7406\u5404\u7a2e\u6578\u64da\u9700\u6c42\u3002\u96a8\u8457\u6578\u64da\u7684\u591a\u6a23\u5316\uff0c\u638c\u63e1\u9019\u4e9b\u6280\u8853\u5c07\u6709\u52a9\u65bc\u63d0\u5347\u6578\u64da\u8655\u7406\u7684\u6548\u7387\u548c\u6e96\u78ba\u6027\u3002\u5982\u679c\u60a8\u6b63\u5728\u5c0b\u627e\u9ad8\u6548\u7684 <a href=\"https:\/\/server.hk\">VPS<\/a> \u89e3\u6c7a\u65b9\u6848\uff0cServer.HK \u63d0\u4f9b\u4e86\u591a\u7a2e\u9078\u64c7\uff0c\u6eff\u8db3\u4e0d\u540c\u696d\u52d9\u9700\u6c42\u3002\u7121\u8ad6\u662f <a href=\"https:\/\/server.hk\">\u9999\u6e2fVPS<\/a> \u9084\u662f\u5176\u4ed6\u670d\u52d9\uff0c\u6211\u5011\u90fd\u80fd\u70ba\u60a8\u63d0\u4f9b\u652f\u6301\u3002<\/p>\n","protected":false},"excerpt":{"rendered":"<p>\u63a2\u7d22 SQL Server \u4e2d\u8655\u7406\u975e\u6574\u6578\u6578\u64da\u7684\u65b0\u65b9\u6cd5\uff0c\u63d0\u5347\u6578\u64da\u7ba1\u7406\u6548\u7387\uff0c\u512a\u5316\u67e5\u8a62\u6027\u80fd\uff0c\u5be6\u73fe\u66f4\u9748\u6d3b\u7684\u6578\u64da\u5206\u6790\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-143693","post","type-post","status-publish","format-standard","hentry","category-database"],"_links":{"self":[{"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/posts\/143693","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=143693"}],"version-history":[{"count":1,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/posts\/143693\/revisions"}],"predecessor-version":[{"id":143694,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/posts\/143693\/revisions\/143694"}],"wp:attachment":[{"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/media?parent=143693"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/categories?post=143693"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/tags?post=143693"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}