Question

I have a table with 3 different IDs. I want to distinct on column 1 and 2 and summarize the values of column 3 (into one field – maybe comma separated string). The summarized field doesn’t have to “look nice” (no problems with: ‘4,3,’ (comma at the end)).
I’m using MS SQL Server 2008.

E.g:

ID1  ID2  ID3
 1    1    5
 1    1    8
 1    2    5
 1    2    8
 2    3   10
 2    3   11
 2    5   12

SELECT …?

The result:

ID1   ID2   Summary
 1     1      5,8
 1     2      5,8
 2     3      10,11
 2     5      12

Answer 1

Edit – removed trailing spaces in the third column

Since you said the summarized field doesn’t have to look nice, try this:

SELECT M1.ID1, M1.ID2,
(
    SELECT convert(nvarchar(50), ID3) + ',' 
    FROM MyTable M2
    WHERE M1.ID1 = M2.ID1 AND M1.ID2 = M2.ID2
    FOR XML PATH('')
) M1
FROM MyTable M1
GROUP BY M1.ID1, M1.ID2

It assumes your table name is called ‘MyTable’. This query results in commas at the end, but should get you started. Using my test database, this was the output:

ID1 ID2  M1
1   1   5,8,
1   2   5,8,
2   3   10,11,
2   5   12,

If you want it cleaned up, this should work (although the query itself is ugly):

SELECT ID1, ID2, left(M1, len(M1) - 1) AS M1
FROM
(
    SELECT M1.ID1, M1.ID2,
    (
        SELECT convert(nvarchar(50), ID3) + ',' 
        FROM MyTable M2
        WHERE M1.ID1 = M2.ID1 AND M1.ID2 = M2.ID2
        FOR XML PATH('')
    ) M1
    FROM MyTable M1
    GROUP BY M1.ID1, M1.ID2
) CleanedUp