Aggregate Function on Uniqueidentifier (GUID)

Question

Let\'s say I have the following table:

category | guid
---------+-----------------------
   A     | 5BC2...
   A     | 6A1C...
   B     | 92A2...

Answer 1

Assuming you're using SQL Server 2005 or later:

;with Numbered as (
     select category,guid,ROW_NUMBER() OVER (PARTITION BY category ORDER BY guid) rn
     from myTable
)
select * from Numbered where rn=1