SQL comma-separated row with Group By clause

Question

I have the following query:

SELECT
  Account,
  Unit,
  SUM(state_fee),
  Code
FROM tblMta
WHERE MTA.Id = '123'
GROUP BY Account,Unit

This of course throws an exception because the Code is not in the group by clause. Each state_fee has a code. How do I get this code to display in 1 record (1 code per state_fee which is multiple state_fee per unit) as a comma-separated list? I looked into different solutions on here but I couldn't find any that worked with a group by.

Answer 1

You want to use FOR XML PATH construct:

SELECT ACCOUNT, 
       unit, 
       SUM(state_fee), 
       Stuff((SELECT ', ' + code 
              FROM   tblmta t2 
              WHERE  t2.ACCOUNT = t1.ACCOUNT 
                     AND t2.unit = t1.unit 
                     AND t2.id = '123' 
              FOR XML PATH('')), 1, 2, '') [Codes] 
FROM   tblmta t1 
WHERE  t1.id = '123' 
GROUP  BY ACCOUNT, 
          unit 

See other examples here:

• SQL same unit between two tables needs order numbers in 1 cell
• SQL Query to get aggregated result in comma seperators along with group by column in SQL Server