如何在SQL中以列的形式轉換表行

Question

您好我有兩個表，我想生成報告，其中所有行將在單行。

tbl_Questions ：

Id  Name
---------
1   Abc
2   Cde
3   xyz
4   MMM

tbl_Reponses ：

Id  QuestionId   Values
------------------------
1      1           123
2      2           456
3      3           444

現在我想得到一個查詢，它會在結果中顯示這樣的時間。

Id Abc Cde xyz MMM
-------------------
1  123 456 444 

如何通過查詢獲得此信息？

Answer 1

使用PIVOT來做到這一點：

SELECT ROW_NUMBER() OVER(ORDER BY [Abc])Id,* FROM
(
SELECT Name,Value FROM tbl_Questions A LEFT JOIN tbl_Reponses B ON A.Id=B.Id
) AS tbl
PIVOT(SUM(Value) FOR Name IN([Abc],[Cde],[xyz],[MMM]))AS pvt

或CrossTab方法

SELECT
    ROW_NUMBER() OVER (ORDER BY MAX(A.Id))Id,
    [Abc] = MAX(CASE WHEN Name = 'Abc' THEN Value END),
    [Cde] = MAX(CASE WHEN Name = 'Cde' THEN Value END),
    [xyz] = MAX(CASE WHEN Name = 'xyz' THEN Value END),
    [MMM] = MAX(CASE WHEN Name = 'xyz' THEN Value END)
FROM tbl_Questions A LEFT JOIN tbl_Reponses B ON A.Id=B.Id

Answer 2

使用Group by

select 
ID
, MIN(CASE WHEN A.NAME ='ABC'
THEN B.VALUES
END) ABC
, MIN(CASE WHEN A.NAME ='cde'
THEN B.VALUES
END) cde
, MIN(CASE WHEN A.NAME ='xyz'
THEN B.VALUES
END) xyz
, ISNULL(MIN(CASE WHEN A.NAME ='mmm'
THEN B.VALUES
END),'') mmm
FROM
tbl_Questions A
inner join tbl_Reponses B
on A.ID=B.ID
group by A.ID