SQLServer行转列实现思路记录

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


复制代码 代码如下:

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