Concatenate one field after GROUP BY

Question

This question have been asked many times in SO but none of the answers is satisfying to my situation.

1. Question 1
2. Question 2
3. Question 3
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Answer 1

Try this:

SELECT [CreatedTime]
      ,[DeletedTime]
      ,[DeletedBy]
      ,[ResourceId]
      ,[AccountId]
      ,STUFF((select ',' + raType.Type 
              from vwAllAssignments raType 
              where raType.AccountId = vwAllAssignments.AccountId and 
                    raType.ResourceId = vwAllAssignments.ResourceId and 
                    raType.DeletedBy is null 
              for xml path('')), 1,1,'') AS [Type]
FROM vwAllAssignments
GROUP BY [ResourceId], [AccountId], [CreatedTime], [DeletedTime], [DeletedBy]

And an index like this should be helpful.

create index IX_vwAllAssignments on vwAllAssignments(AccountId, ResourceId, DeletedBy) include(Type)