"Vikrant Rathore" <vikrant@chemquick.com> writes:
> I have been able to run the following query successfully on postgresl-
> 6.3.2 but unable to run the same in Postgresql-6.5.2.
> select
> a.offer_id,a.comp_id,prod_name,date(offer_date),time(offer_date),
> ...
> group by a.offer_id
> ...
If you group by a.offer_id, then your select list can't refer to
any other columns except as aggregate-function arguments. For
example, it would make sense to ask for min(a.comp_id) to get the
smallest comp_id out of each group of rows with the same offer_id.
But that group of rows doesn't necessarily all have the same comp_id,
so you can't expect to ask for unvarnished comp_id and get a well-
defined answer.
Before about v6.5, Postgres was fairly lax about checking for this
logical error (which is also a violation of the SQL standard), and
would in fact give you back some randomly-chosen comp_id value.
Recent versions detect the error, however.
regards, tom lane
