Question

I can’t seem to get this one. So I have a table like this:

RowID    UserID  Type    Data
1        A       A       1
2        A       A       2
3        A       B       1
4        A       B       2
5        B       A       1
6        B       A       2
7        B       B       1
8        B       B       2

And I need to group this table by UserID and Type and then return the RowID for the record in each group that holds the MIN value in the Data column.

So for my result set would be:
1
3
5
7

Answer 1

For SQL Server >= 2005, you can do:

select RowID
from (
    select RowID,
        Rank() over (Partition BY UserID, Type 
            order by Data) as Rank
    from MyTable
) tmp
where Rank = 1

SQL Fiddle Example

For SQL Server < 2005, you can do:

select t.RowID
from MyTable t
inner join (
    select UserID, Type, min(Data) as MinData
    from MyTable
    group by UserID, Type 
) tm on t.UserID = tm.UserID and t.Type = tm.Type
    and t.Data = tm.MinData

SQL Fiddle Example