>>If you want the fastest result, then try packed value solution from that blog.
>
>Thanks

select PK, cast(substring(MaxValue,11,10) as int) as ChildPK, MaxChildField 
from (select PK, Max(ChildField) as MaxChildField, 
max(cast(ChildField as char(10)) + cast(ChildPKField as char(10))) as MaxValue from myTables GROUP BY PK) X