SQLServer行转列实现思路记录

时间:2020-12-16 人气:0

SQLServer行转列的sql语句有很多，可以使用静态的、动态的、Case When等等，均能实现

最近面试遇到了一道面试题，顿时有点迷糊，只说出了思路，后来百度了一下，整理了一下思路，于是记录下来，方便以后学习。（面试题请参见附件）

相关的数据表：

1.Score表

2.[User]表

SQL语句如下：

--方法一：静态SQL

 
SELECT * FROM 
(SELECT UID,Name, Score,ScoreName FROM Score,[User] WHERE Score.UID=[User].ID) AS SourceTable 
PIVOT(AVG(Score)FOR ScoreName IN ([英语], [数学])) AS a 

--方法二：动态SQL

复制代码代码如下:

 
DECLARE @s NVARCHAR(4000) 
SELECT @s = ISNULL(@s + ',', '') + QUOTENAME(ScoreName) 
FROM (select distinct ScoreName from Score) as A ---列名不要重复 

Declare @sql NVARCHAR(4000) 
SET @sql=' 
select r.* from 
(select UID,Name,ScoreName,Score from Score,[User] where Score.UID=[User].ID) as t 
pivot 
( 
max(t.Score) 
for t.ScoreName in ('+@s+') 
) as r' 
EXEC( @sql) 

--方法三：Case When

复制代码代码如下:

 
select 
row_number() OVER(ORDER BY [User].ID) as 编号, 
UID as 用户编号, 
Name as 姓名, 
max(case ScoreName when '英语' then Score else 0 end) 英语, 
max(case ScoreName when '数学' then Score else 0 end) 数学 
from Score,[User] WHERE Score.UID=[User].ID 
group by UID,[User].ID,Name 

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