SQL Server 查询横表变竖表的sql语句简析

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                              主表

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                 人名表

按照常规查询

SELECT s.SName,c.CName,s2.SCgrade

  FROM S s INNER JOIN SC s2 ON s2.SNo = s.SNo INNER JOIN C c ON c.CNo = s2.CNo

那么结果是这样的

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但是这是横表 不是我想看到的结果。

我们要看到这样的结果：

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那么怎么办呢？
第一种写法：

代码如下:

 
SELECT w.SName,sum(case when w.CNo= 1 then w.SCgrade ELSE 0 END) AS '语文',sum(case WHEN w.CNo =2 THEN w.SCgrade ELSE 0 END) AS '数学',sum(case when w.CNo= 3 then w.SCgrade ELSE 0 END) AS '英语' 
FROM 
(SELECT s.SNo,s.SName,s2.CNo,s2.SCgrade FROM s s INNER JOIN SC s2 ON s2.SNo = s.SNo WHERE s.SNo IN (SELECT c.SNo FROM sc c GROUP BY c.SNo )) 
AS w GROUP BY w.SName 

代码如下:

 
SELECT s.SName,sum(case when s2.CNo= 1 then s2.SCgrade ELSE 0 END) AS '语文',sum(case WHEN s2.CNo =2 THEN s2.SCgrade ELSE 0 END) AS '数学',sum(case when s2.CNo= 3 then s2.SCgrade ELSE 0 END) AS '英语' 
FROM 
S s INNER JOIN SC s2 ON s2.SNo = s.SNo 
INNER JOIN C c ON c.CNo = s2.CNo 
GROUP BY s.SNo,s.SName 

（编辑：李大同）

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