> Zeugswetter Andreas SB <ZeugswetterA@wien.spardat.at> writes:
> > Informix and DB/2 allow column numbering in the group by clause.
>
> What do they do with
>
> SELECT foo AS bar FROM table GROUP BY bar
>
> What do they do if bar is the real name of another column in
> the table?
They don't allow labels, only numbers,
(SELECT foo AS bar FROM table GROUP BY 1)
In the special case where a label collides with a colname,
we need to use the colname, because that behavior is
ruled by the standard (since it doesn't allow a label).
The order by clause is the other way around.
DB Vendors probably disallow this syntax,
because the two different interpretations would be a bit awkward.
Best would of course be if the standard allowed labels in the
group by and where clause and take label before colname.
Andreas