> You can't include an aggregate in the select if you don't group by > non-aggregates, so it should be: > > select max(t1."When"), t1."Pt_Id", t2."DateOfBirth" > from "PtStaffAccess" t1, "Person" t2 > where t1."Pt_Id" = t2.id > group by t1."Pt_Id", t2."DateOfBirth"; I was aware that I could alternatively group by all the columns, but that actually just highlights the redundancy even more--consider your second example: select max(t1."When"), t2.id , t2."DateOfBirth" from "PtStaffAccess" t1, "Person" t2 where t1."Pt_Id" = t2.id group by t2.id, t2."DateOfBirth"; Given that t2.id is the primary key, grouping by any other column of t2 is really redundant. I know *what* SQL won't allow me to do, I'm interested in knowing if there's some reason *why* other than historical... -- Scott Ribe scott_ribe@xxxxxxxxxxxxxxx http://www.killerbytes.com/ (303) 722-0567 voice -- Sent via pgsql-general mailing list (pgsql-general@xxxxxxxxxxxxxx) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-general
