Re: GROUP BY & implicit sorts

Just live in hope that no-one decides to speed up your applications by switching
on parallel queries !

Also, Oracle could do a:

    sort (group by) nosort
by using an index to acquire the data,
but if a driving condition were:

    where X <= {const}
then, in principle, Oracle could use the index in descending order, and leave
your output sorted the wrong way round.

--
Jonathan Lewis
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Charlie Edwards wrote in message ...


>This is just an academic question.

>

>Recently I read somewhere that Oracle does not guarantee that a GROUP

>BY will always sort the result set (as if you did an ORDER BY).

>

>Now I always assumed that this was the case (probably just because in

>my experience this always seemed to happen).

>

>Is Oracle just covering itself here?  Along the lines of "we never

>actually promised that GROUP BY will do a sort, so if we find a better

>way of grouping without sorting, don't blame us".

>

>Has anyone ever had experience of a GROUP BY that didn't sort as

>expected?

>

>I've left code with a GROUP BY but no ORDER BY in applications the

>length and breadth of England - hope my name isn't at the top ;-)

>

>CE