Have a piece of SQL:
select INSTNUM,'',IDXCOD,INSTFREE,INSTFREE2,YLD
from HIST h where DAT =
(select max(DAT) from HIST h2 where h.INSTNUM = h2.INSTNUM)
go
which runs fine, albeit a bit slow.
An unique clustered index exists for
INSTNUM, DAT
The subquery uses this, the outer query does...