{"id":160007,"date":"2024-11-03T19:31:03","date_gmt":"2024-11-03T11:31:03","guid":{"rendered":"https:\/\/server.hk\/cnblog\/160007\/"},"modified":"2024-11-03T19:31:04","modified_gmt":"2024-11-03T11:31:04","slug":"mssql-%e6%95%99%e7%a8%8b-sql-%e5%87%bd%e6%95%b8","status":"publish","type":"post","link":"https:\/\/server.hk\/cnblog\/160007\/","title":{"rendered":"MSSQL \u6559\u7a0b SQL \u51fd\u6578"},"content":{"rendered":"<h1 id=\"mssql-%e6%95%99%e7%a8%8b-sql-%e5%87%bd%e6%95%b8-yYhdLriAYi\">MSSQL \u6559\u7a0b SQL \u51fd\u6578<\/h1>\n<p>\u5728\u6578\u64da\u5eab\u7ba1\u7406\u7cfb\u7d71\u4e2d\uff0cSQL\uff08\u7d50\u69cb\u5316\u67e5\u8a62\u8a9e\u8a00\uff09\u662f\u7528\u65bc\u67e5\u8a62\u548c\u64cd\u4f5c\u6578\u64da\u7684\u4e3b\u8981\u8a9e\u8a00\u3002Microsoft SQL Server\uff08MSSQL\uff09\u662f\u4e00\u500b\u5ee3\u6cdb\u4f7f\u7528\u7684\u95dc\u806f\u6578\u64da\u5eab\u7ba1\u7406\u7cfb\u7d71\uff0c\u63d0\u4f9b\u4e86\u591a\u7a2e\u5f37\u5927\u7684 SQL \u51fd\u6578\u4f86\u5e6b\u52a9\u7528\u6236\u9032\u884c\u6578\u64da\u8655\u7406\u548c\u5206\u6790\u3002\u672c\u6587\u5c07\u4ecb\u7d39\u4e00\u4e9b\u5e38\u7528\u7684 MSSQL SQL \u51fd\u6578\uff0c\u4e26\u63d0\u4f9b\u76f8\u61c9\u7684\u793a\u4f8b\uff0c\u4ee5\u5e6b\u52a9\u8b80\u8005\u66f4\u597d\u5730\u7406\u89e3\u548c\u4f7f\u7528\u9019\u4e9b\u51fd\u6578\u3002<\/p>\n<h2 id=\"1-%e8%81%9a%e5%90%88%e5%87%bd%e6%95%b8-yYhdLriAYi\">1. \u805a\u5408\u51fd\u6578<\/h2>\n<p>\u805a\u5408\u51fd\u6578\u662f\u7528\u65bc\u8a08\u7b97\u4e00\u7d44\u503c\u7684\u55ae\u4e00\u503c\uff0c\u5e38\u898b\u7684\u805a\u5408\u51fd\u6578\u5305\u62ec\uff1a<\/p>\n<ul>\n<li><code>COUNT()<\/code>\uff1a\u8a08\u7b97\u884c\u6578\u3002<\/li>\n<li><code>SUM()<\/code>\uff1a\u8a08\u7b97\u6578\u503c\u7684\u7e3d\u548c\u3002<\/li>\n<li><code>AVG()<\/code>\uff1a\u8a08\u7b97\u6578\u503c\u7684\u5e73\u5747\u503c\u3002<\/li>\n<li><code>MIN()<\/code>\uff1a\u8fd4\u56de\u6700\u5c0f\u503c\u3002<\/li>\n<li><code>MAX()<\/code>\uff1a\u8fd4\u56de\u6700\u5927\u503c\u3002<\/li>\n<\/ul>\n<p>\u4f8b\u5982\uff0c\u5047\u8a2d\u6709\u4e00\u500b\u540d\u70ba <code>Sales<\/code> \u7684\u8868\u683c\uff0c\u5305\u542b <code>Amount<\/code> \u6b04\u4f4d\uff0c\u60a8\u53ef\u4ee5\u4f7f\u7528\u4ee5\u4e0b\u67e5\u8a62\u4f86\u8a08\u7b97\u7e3d\u92b7\u552e\u984d\uff1a<\/p>\n<pre><code>SELECT SUM(Amount) AS TotalSales FROM Sales;<\/code><\/pre>\n<h2 id=\"2-%e5%ad%97%e4%b8%b2%e5%87%bd%e6%95%b8-yYhdLriAYi\">2. \u5b57\u4e32\u51fd\u6578<\/h2>\n<p>\u5b57\u4e32\u51fd\u6578\u7528\u65bc\u8655\u7406\u548c\u64cd\u4f5c\u5b57\u4e32\u6578\u64da\u3002\u5e38\u898b\u7684\u5b57\u4e32\u51fd\u6578\u5305\u62ec\uff1a<\/p>\n<ul>\n<li><code>LEN()<\/code>\uff1a\u8fd4\u56de\u5b57\u4e32\u7684\u9577\u5ea6\u3002<\/li>\n<li><code>UPPER()<\/code>\uff1a\u5c07\u5b57\u4e32\u8f49\u63db\u70ba\u5927\u5beb\u3002<\/li>\n<li><code>LOWER()<\/code>\uff1a\u5c07\u5b57\u4e32\u8f49\u63db\u70ba\u5c0f\u5beb\u3002<\/li>\n<li><code>SUBSTRING()<\/code>\uff1a\u63d0\u53d6\u5b57\u4e32\u7684\u4e00\u90e8\u5206\u3002<\/li>\n<li><code>CONCAT()<\/code>\uff1a\u9023\u63a5\u5169\u500b\u6216\u591a\u500b\u5b57\u4e32\u3002<\/li>\n<\/ul>\n<p>\u4f8b\u5982\uff0c\u60a8\u53ef\u4ee5\u4f7f\u7528 <code>SUBSTRING()<\/code> \u51fd\u6578\u4f86\u63d0\u53d6\u5b57\u4e32\u7684\u7279\u5b9a\u90e8\u5206\uff1a<\/p>\n<pre><code>SELECT SUBSTRING(Name, 1, 5) AS ShortName FROM Customers;<\/code><\/pre>\n<h2 id=\"3-%e6%97%a5%e6%9c%9f%e5%92%8c%e6%99%82%e9%96%93%e5%87%bd%e6%95%b8-yYhdLriAYi\">3. \u65e5\u671f\u548c\u6642\u9593\u51fd\u6578<\/h2>\n<p>MSSQL \u63d0\u4f9b\u4e86\u591a\u7a2e\u65e5\u671f\u548c\u6642\u9593\u51fd\u6578\uff0c\u7528\u65bc\u8655\u7406\u65e5\u671f\u548c\u6642\u9593\u6578\u64da\u3002\u5e38\u898b\u7684\u65e5\u671f\u548c\u6642\u9593\u51fd\u6578\u5305\u62ec\uff1a<\/p>\n<ul>\n<li><code>GETDATE()<\/code>\uff1a\u8fd4\u56de\u7576\u524d\u7684\u65e5\u671f\u548c\u6642\u9593\u3002<\/li>\n<li><code>DATEDIFF()<\/code>\uff1a\u8a08\u7b97\u5169\u500b\u65e5\u671f\u4e4b\u9593\u7684\u5dee\u7570\u3002<\/li>\n<li><code>DATEADD()<\/code>\uff1a\u5728\u6307\u5b9a\u7684\u65e5\u671f\u4e0a\u6dfb\u52a0\u6642\u9593\u9593\u9694\u3002<\/li>\n<li><code>FORMAT()<\/code>\uff1a\u683c\u5f0f\u5316\u65e5\u671f\u548c\u6642\u9593\u3002<\/li>\n<\/ul>\n<p>\u4f8b\u5982\uff0c\u60a8\u53ef\u4ee5\u4f7f\u7528 <code>DATEDIFF()<\/code> \u51fd\u6578\u4f86\u8a08\u7b97\u5169\u500b\u65e5\u671f\u4e4b\u9593\u7684\u5929\u6578\uff1a<\/p>\n<pre><code>SELECT DATEDIFF(DAY, '2023-01-01', GETDATE()) AS DaysSinceNewYear;<\/code><\/pre>\n<h2 id=\"4-%e6%a2%9d%e4%bb%b6%e5%87%bd%e6%95%b8-yYhdLriAYi\">4. \u689d\u4ef6\u51fd\u6578<\/h2>\n<p>\u689d\u4ef6\u51fd\u6578\u7528\u65bc\u6839\u64da\u7279\u5b9a\u689d\u4ef6\u8fd4\u56de\u4e0d\u540c\u7684\u503c\u3002\u6700\u5e38\u7528\u7684\u689d\u4ef6\u51fd\u6578\u662f <code>CASE<\/code> \u51fd\u6578\u3002\u5b83\u7684\u57fa\u672c\u8a9e\u6cd5\u5982\u4e0b\uff1a<\/p>\n<pre><code>SELECT \n    CASE \n        WHEN Condition1 THEN Result1\n        WHEN Condition2 THEN Result2\n        ELSE DefaultResult\n    END AS ResultColumn\nFROM TableName;<\/code><\/pre>\n<p>\u4f8b\u5982\uff0c\u60a8\u53ef\u4ee5\u4f7f\u7528 <code>CASE<\/code> \u51fd\u6578\u4f86\u6839\u64da\u92b7\u552e\u984d\u7684\u7bc4\u570d\u8fd4\u56de\u4e0d\u540c\u7684\u8a55\u7d1a\uff1a<\/p>\n<pre><code>SELECT \n    Amount,\n    CASE \n        WHEN Amount &gt;= 1000 THEN '\u9ad8'\n        WHEN Amount &gt;= 500 THEN '\u4e2d'\n        ELSE '\u4f4e'\n    END AS SalesRating\nFROM Sales;<\/code><\/pre>\n<h2 id=\"%e7%b8%bd%e7%b5%90-yYhdLriAYi\">\u7e3d\u7d50<\/h2>\n<p>\u672c\u6587\u4ecb\u7d39\u4e86 MSSQL \u4e2d\u7684\u4e00\u4e9b\u5e38\u7528 SQL \u51fd\u6578\uff0c\u5305\u62ec\u805a\u5408\u51fd\u6578\u3001\u5b57\u4e32\u51fd\u6578\u3001\u65e5\u671f\u548c\u6642\u9593\u51fd\u6578\u4ee5\u53ca\u689d\u4ef6\u51fd\u6578\u3002\u9019\u4e9b\u51fd\u6578\u5728\u6578\u64da\u8655\u7406\u548c\u5206\u6790\u4e2d\u626e\u6f14\u8457\u91cd\u8981\u7684\u89d2\u8272\uff0c\u5e6b\u52a9\u7528\u6236\u66f4\u6709\u6548\u5730\u7ba1\u7406\u548c\u64cd\u4f5c\u6578\u64da\u3002\u82e5\u60a8\u9700\u8981\u9032\u4e00\u6b65\u4e86\u89e3\u5982\u4f55\u5728 <a href=\"https:\/\/server.hk\">\u9999\u6e2f\u4f3a\u670d\u5668<\/a> \u4e0a\u4f7f\u7528 MSSQL\uff0c\u6216\u5c0b\u627e\u5408\u9069\u7684 <a href=\"https:\/\/server.hk\">VPS&lt;\/a<\/p>\n","protected":false},"excerpt":{"rendered":"<p>\u63a2\u7d22 MSSQL \u6559\u7a0b\uff0c\u6df1\u5165\u4e86\u89e3 SQL \u51fd\u6578\u7684\u4f7f\u7528\uff0c\u63d0\u5347\u6578\u64da\u8655\u7406\u548c\u67e5\u8a62\u6548\u7387\uff0c\u9069\u5408\u5404\u7d1a\u5225\u7684\u958b\u767c\u8005\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-160007","post","type-post","status-publish","format-standard","hentry","category-database"],"_links":{"self":[{"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/posts\/160007","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=160007"}],"version-history":[{"count":1,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/posts\/160007\/revisions"}],"predecessor-version":[{"id":160008,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/posts\/160007\/revisions\/160008"}],"wp:attachment":[{"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/media?parent=160007"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/categories?post=160007"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/tags?post=160007"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}