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SQLServer行轉列

最近面試遇到了一道面試題,頓時有點迷糊,隻說出了思路,後來百度了一下,整理了一下思路,于是記錄下來,友善以後學習。(面試題請參見附件)

相關的資料表:

1.Score表

SQLServer行轉列

2.[User]表

SQLServer行轉列

SQL語句如下:

--方法一:靜态SQL

SELECT * FROM

(SELECT UID,Name, Score,ScoreName FROM Score,[User] WHERE Score.UID=[User].ID) AS SourceTable

PIVOT(AVG(Score)FOR ScoreName IN ([英語], [數學])) AS a

--方法二:動态SQL

DECLARE @s NVARCHAR(4000)  

SELECT @s = ISNULL(@s + ‘,‘, ‘‘) +  QUOTENAME(ScoreName)  

FROM  (select distinct ScoreName from Score) as A ---列名不要重複  

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

select  

  row_number() OVER(ORDER BY [User].ID) as 編号,

  UID as 使用者編号,

  Name as 姓名,

  max(case ScoreName when ‘英語‘ then Score else 0 end) 英語,

  max(case ScoreName when ‘數學‘ then Score else 0 end) 數學

from Score,[User] WHERE Score.UID=[User].ID

group by UID,[User].ID,Name