Question

I am trying to write a sql statement that creates a pivot table.

The data is a list of survey responses and is made from a join query involving tables respondent, response and answer. The answer table is structured as below:

______________________________________________________________
|AnswerID|ResponseID|QuestionID|AnswerComment                |
|      1 |        1 |        1 |This is answer 1             |
|      2 |        1 |        2 |This is answer 2             |
|      3 |        1 |        3 |This is answer 3             |
|      4 |        2 |        1 |Answer 1 Respondent 2        |
|      5 |        2 |        3 |Resp 2, No Q.2               |
|      6 |        3 |        2 |I answered Q.2 only          |
|____________________________________________________________|

Respondent looks like:

______________________________________________________________
|RespondentID|GivenName|Surname|age, gender, blah blah       |
|____________________________________________________________|

Response:

______________________________________________________________
|ResponseID|ResponseDate|RespondentID|Attachment             |
|____________________________________________________________|

and Question:

_____________________________________________________
|QuestionID|QuestionNumber|QuestionText|            |
|___________________________________________________|

I want my output in the form of:

________________________________________________________________________________________
|RespondentInfo|ResponseDate|1                     |2                  |3               |
|Respondent 1  |15/10/2012  |This is answer 1      |This is answer 2   |This is answer 3|
|Respondent 2  |17/10/2012  |Answer 1 Respondent 2 |                   |Resp 2, No Q.2  |
|Respondent 3  |19/10/2012  |                      |I answered Q.2 only|                |
|______________________________________________________________________________________|

I want to get one line per respondent with each answer in the corresponding column. The query I have created – although it pivots the answers to the correct columns – provides a new row for each answer with nulls in all the blank columns.

My sql:

SELECT Respondent, ResponseDate, 
         [1], [2], [3]
FROM  (
       SELECT  Respondent.Surname + ', ' + FirstName as RespondentInfo, 
               Response.ResponseDate, 
               isnull(Answer.AnswerComment, '') as Answer, 
               Qustion.QuestionNumber
       FROM    Answer INNER JOIN
                Question ON Answer.QuestionID = Question.QuestionID INNER JOIN
                   Response ON Answer.ResponseID = Response.ResponseID INNER JOIN
                   Respondent ON Response.RespondentID = Respondent.RespondentID
       ) as ResponseQuery
PIVOT (
    max(Answer)
FOR ResponseQuery.QuestionNumber in ([1], [2], [3])
       ) AS OutputTable

I think the issue is because I am not using an aggregate function so have defaulted to max(). Can anyone point me in the right direction.

Apologies if my question is too verbose.

Answer 1

The problem is the source, not the pivot.

It’s hard to tell without seeing the other tables, but using your example table

select ResponseID, [1],[2],[3] from 
    (select ResponseID, AnswerComment, QuestionID from yourtable) s
PIVOT (max(AnswerComment) FOR QuestionID in ([1], [2], [3]) ) AS OutputTable

produces the output in the form you’re after.

If you can’t figure out how to adjust the source to provide the data you want, you can join after the pivot by adding something like…

 inner join Response on OutputTable.ResponseID = Response.ResponseID 

after the above pivot to give

select Response.ResponseDate, [1],[2],[3] from 
    (select ResponseID, AnswerComment, QuestionID from yourtable) s
PIVOT (max(AnswerComment) FOR QuestionID in ([1], [2], [3]) ) AS OutputTable
inner join Response on OutputTable.ResponseID = Response.ResponseID 

etc…