How do I select the first row per group in an SQL Query?

Question

I\'ve got this SQL query:

SELECT   Foo, Bar, SUM(Values) AS Sum
FROM     SomeTable
GROUP BY Foo, Bar
ORDER BY Foo DESC, Sum DESC

This resul

Answer 1

Curious. Only way I could get this to work was by using a temporary holding table in memory. (TSQL syntax)

-- original test data
declare @sometable table ( foo int, bar int, value int )

insert into @sometable values (1, 5, 10)
insert into @sometable values (1, 4, 20)
insert into @sometable values (2, 1, 1)
insert into @sometable values (2, 1, 10)
insert into @sometable values (2, 1, 1)
insert into @sometable values (2, 2, 13)
insert into @sometable values (3, 4, 25)
insert into @sometable values (3, 5, 1)
insert into @sometable values (3, 1, 1)
insert into @sometable values (3, 1, 1)
insert into @sometable values (3, 1, 1)
insert into @sometable values (3, 1, 1)
insert into @sometable values (3, 1, 1)

-- temp table for initial aggregation
declare @t2 table (foo int, bar int, sums int)
insert into @t2
select foo, bar, sum(value) 
from @sometable
group by foo, bar

-- final result
select foo, bar, sums
from @t2 a
where sums = 
    (select max(sums) from @t2 b 
     where b.foo = a.foo)