Re: Bug: aliasing in ORDER BY when UNIONing

On Sun, Feb 18, 2001 at 08:24:20PM -0500, Tom Lane wrote:
> Marko Kreen <marko(at)l-t(dot)ee> writes:
> > What works:
> > # select o.id from op o union all SELECT -1 order by id;
>
> This is valid SQL.
>
> > # select o.id from op o union all SELECT -1 order by o.id;
> > ERROR: Relation 'o' does not exist
>
> This is not valid SQL. For one thing, the table alias "o" is not
> visible outside the first component SELECT.
>
> Yes, I know 7.0 took it... but its handling of ORDER BY on UNION
> was pretty darn broken.

Doh. But if I have several tables with a field 'id'? Then only
way is to use the column number? But the query is big and composed
of several sources, fields and other stuff is separated - oh
well... Thankfully the field is not 'id' so maybe its not that
bad.

Anyway such stuff should be documented I guess. From current
docs I read that it should work. I would have expected that one
of the select's aliases would be transferred to ORDER BY but its
not possible?

--
marko