Re: GROUP BY & implicit sorts

From: Richard Foote <richard.foote_at_bigpond.com>
Date: Thu, 25 Jul 2002 00:26:37 +1000
Message-ID: <mHy%8.43163$Hj3.129026@newsfeeds.bigpond.com>

Hi Charlie,

A group by does do implicit sorts, *sometimes*. It's the sometimes and the fact that dependencies can change (such as a new index or parallel clause) that doesn't guarantee the behaviour a group by now and the same group by next time in returning the data in the same way.

Order By is the *only* way to have that guarantee.

Cheers

Richard
"Charlie Edwards" <Charlie3101_at_hotmail.com> wrote in message news:db479d88.0207240608.698779d7_at_posting.google.com...
> "Niall Litchfield" <n-litchfield_at_audit-commission.gov.uk> wrote in message
news:<3d3e65c3$0$234$ed9e5944_at_reading.news.pipex.net>...
> > "Charlie Edwards" <Charlie3101_at_hotmail.com> wrote in message
> > news:db479d88.0207240019.54e7b6f9_at_posting.google.com...
> > > This is just an academic question.
> >
> > Oh no it isn't
> > >
> Well, it is an academic question for me, as I don't rely on it anymore!

>


> >

> > See

> >
> >

http://groups.google.com/groups?hl=en&lr=&ie=UTF-8&selm=36886d96.28433695%40 192.86.155.100&rnum=7
> >
> > for an example of group by not being the same as order by. Indexes and
> > parallel query may well screw up your assumption. .
> >

>

> I assume nothing anymore!

>

> Thanks very much for this, Niall.
> Maybe this should have been in the list of "Oracle Myths" from a few weeks
ago.

>

> But I wonder, was it _ever_ the case that GROUP BY did implicit sorts?
>
> CE
Received on Wed Jul 24 2002 - 09:26:37 CDT