Re: pg, mysql comparison with "group by" clause

Well...

An additional gripe is that this isn't a good feature (standard or not).
Oracle doesn't do it. Db2 doesn't do it. I strongly suggest you guys
don't
do it.

If you wanna do the optimizations under the covers, cool, but I can't
imagine how this would be useful other than for saving some typing...

Seems more trouble than it's worth and changes a concept that's tried
and true for many years.

Regards,
Anthony

-----Original Message-----
From: pgsql-sql-owner(at)postgresql(dot)org
[mailto:pgsql-sql-owner(at)postgresql(dot)org] On Behalf Of Tom Lane
Sent: Thursday, October 13, 2005 2:50 PM
To: Scott Marlowe
Cc: Greg Stark; Stephan Szabo; Rick Schumeyer; pgsql-sql(at)postgresql(dot)org
Subject: Re: [SQL] pg, mysql comparison with "group by" clause

>>>> In standard SQL you have to
>>>> write GROUP BY ... and list every single column you need from the
master
>>>> table.

This thread seems to have gone off on a tangent that depends on the
assumption that the above is a correct statement. It's not. It *was*
true, in SQL92, but SQL99 lets you omit unnecessary GROUP BY columns.

The gripe against mysql, I think, is that they don't enforce the
conditions that guarantee the query will give a unique result.

The gripe against postgres is that we haven't implemented the SQL99
semantics yet.

regards, tom lane

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