首先是三张表， CNo对应的是课程，在这里我就粘贴了。            

GROUP BY s.SNo,

SELECT w.SName,
s.SName
sum(case when w.CNo= 3 then w.SCgrade ELSE 0 END) AS '英语'

那么怎么办呢？
第一种写法：
SELECT s.SName,

按照常规查询

FROM

那么结果是这样的

但是这是横表 不是我想看到的结果。

复制代码 代码如下:

sum(case when s2.CNo= 3 then s2.SCgrade ELSE 0 END) AS '英语'
sum(case WHEN w.CNo =2 THEN w.SCgrade ELSE 0 END) AS '数学',
第二种写法：
INNER JOIN C c ON c.CNo = s2.CNo

复制代码 代码如下:

AS w GROUP BY w.SName
S s INNER JOIN SC s2 ON s2.SNo = s.SNo

我们要看到这样的结果：

这是我工作遇到过得情况，总结下来。如果有遇到这种情况的话可以参考下。

sum(case when s2.CNo= 1 then s2.SCgrade ELSE 0 END) AS '语文',
FROM

主表

(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 ))

sum(case when w.CNo= 1 then w.SCgrade ELSE 0 END) AS '语文',

sum(case WHEN s2.CNo =2 THEN s2.SCgrade ELSE 0 END) AS '数学',

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

人名表