Question

Sorry for the lame title, my descriptive skills are poor today.

In a nutshell, I have a query similar to the following:

SELECT P.LAST_NAME, P.FIRST_NAME, D.DEMO_GROUP
FROM PERSON P
JOIN PERSON_DEMOGRAPHIC PD ON PD.PERSON_ID = P.PERSON_ID
JOIN DEMOGRAPHIC D ON D.DEMOGRAPHIC_ID = PD.DEMOGRAPHIC_ID

This returns output like this:

LAST_NAME      FIRST_NAME     DEMO_GROUP
---------------------------------------------
Johnson        Bob            Male
Smith          Jane           Female
Smith          Jane           Teacher
Beeblebrox     Zaphod         Male
Beeblebrox     Zaphod         Alien
Beeblebrox     Zaphid         Politician

I would prefer the output be similar to the following:

LAST_NAME      FIRST_NAME     Male           Female         Teacher        Alien          Politician
---------------------------------------------------------------------------------------------------------
Johnson        Bob            1              0              0              0              0
Smith          Jane           0              1              1              0              0
Beeblebrox     Zaphod         1              0              0              1              1

The number of rows in the DEMOGRAPHIC table varies, so I can’t say with certainty how many columns I need. The query needs to be flexible.

Yes, it would be trivial to do this in code. But this query is one piece of a complicated set of stored procedures, views, and reporting services, many of which are outside my sphere of influence. I need to produce this output inside the database to avoid breaking the system. Any ideas?

This is MS SQL Server 2005, by the way.

Thanks.

Answer 1

You can use the PIVOT function. Here´s a piece of code. This function needs the columns in advance, but if you do not know the number of columns, you should make a dynamic sql query. Take a look at this answer.

SELECT LAST_NAME, FIRST_NAME, [Male], [Female], [Alien], [Politician], [Teacher]
FROM 
(SELECT LAST_NAME, FIRST_NAME, DEMO_GROUP
FROM Person) p
PIVOT
(
COUNT (DEMO_GROUP)
FOR DEMO_GROUP IN
( [Male], [Female], [Alien], [Politician], [Teacher] )
) AS pvt
ORDER BY LAST_NAME