Sql 如何将两列转置到行

Sql 如何将两列转置到行,sql,sql-server,Sql,Sql Server,我目前将此表用于调查,在调查中,我只需要对第3个问题的回答和评论,而只需要对第4个问题的评论 +---------------------------------------------------+ | Employee | SurveyNo | Question | Answer | Comment | +----------+----------+----------+--------+---------+ | 100 | 1 | 1 |Neutral

我目前将此表用于调查,在调查中,我只需要对第3个问题的回答和评论,而只需要对第4个问题的评论

+---------------------------------------------------+
| Employee | SurveyNo | Question | Answer | Comment |
+----------+----------+----------+--------+---------+
|   100    |    1     |    1     |Neutral |   NULL  |
|   100    |    1     |    2     |  Hard  |   NULL  |
|   100    |    1     |    3     |  Easy  |  asdfs  |
|   100    |    1     |    4     |  NULL  |  ssafa  |
|   200    |    2     |    1     |  Hard  |   NULL  |
|   200    |    2     |    2     |  Hard  |   NULL  |
|   200    |    2     |    3     |  Easy  |  asdfs  |
|   200    |    2     |    4     |  NULL  |   NULL  |
+---------------------------------------------------+
我要找的是这样的东西

+--------------------------------------------------------------------------------+
| Employee | surveyNo |Question1 | Question2 | Question3 | CommentsQ3 | Comments |
+----------+----------+----------+-----------+-----------+------------+----------+
|   100    |    1     | Neutral  |    Hard   |   Easy    |   asdfs    |  ssafa   |
|   200    |    2     |   Hard   |    Hard   |   Easy    |   asdfs    |          |
+--------------------------------------------------------------------------------+
目前我可以得到每一个问题,但不是评论,我只想得到第三个问题的评论和第四个问题的评论

但是当我包含注释时,我开始得到重复的行

SELECT  Employee,surveyNo,[1] as Question1,[2] as Question2,[3] as Question3
FROM
(
SELECT Employee,surveyNo,answer FROM Surveys WHERE Question in (1,2,3)
) d
pivot
(
max(answer)
for Question in ([1],[2],[3])
) piv

您可以执行条件聚合:

SELECT Employee, surveyNo,
       MAX(CASE WHEN Question = 1 THEN Answer END) AS Question1 ,
       . . . 
       MAX(CASE WHEN Question = 1 THEN Comment END) AS CommentsQ1,
       . . .
FROM Surveys 
WHERE Question in (1,2,3)
GROUP BY Employee, surveyNo;

谢谢我想我把自己搞得太复杂了。它的表现也非常快。
SELECT Employee, surveyNo,
       MAX(CASE WHEN Question = 1 THEN Answer END) AS Question1 ,
       . . . 
       MAX(CASE WHEN Question = 1 THEN Comment END) AS CommentsQ1,
       . . .
FROM Surveys 
WHERE Question in (1,2,3)
GROUP BY Employee, surveyNo;