Re: Questionable behavior regarding aliasing

Jim Nasby <Jim.Nasby@BlueTreble.com> writes:
> I fat-fingered a view create and ended up with this:
> ...
>        , schemaname, relname -- other
>        now
>        , d_now, ...
> I was about to report this as a bug until Marko Tiikkaja pointed out on 
> IRC that now was being treated as an alias for relname.

> I'm not sure if this is required by the spec, but can we at least emit a 
> WARNING if not reject this case outright?

SQL:2011 gives the syntax of a SELECT list element as
   <derived column> ::=     <value expression> [ <as clause> ]   <as clause> ::=     [ AS ] <column name>

There is not a lot of room for argument there.  And we got a lot of
complaints back when we didn't support omitting AS.

If we're going to get into the business of emitting warnings for
required-by-SQL-spec constructs, I'm not sure that this one is
where I'd start.  Unqualified outer references seem to catch a
lot more people.
        regards, tom lane