Re: GROUP BY column alias?

On Fri, Feb 19, 2010 at 12:07:42AM -0500, Tom Lane wrote:
> Lew <noone(at)lwsc(dot)ehost-services(dot)com> writes:
> > Eric B. Ridge wrote:
> >> That explains it. Thanks. Breaks the rule of least surprise,
> >> but it is SQL.
>
> SQL:1999 and later use a slightly different definition which is not
> entirely upward compatible with SQL-92. In most cases, however,
> PostgreSQL will interpret an ORDER BY or GROUP BY expression the
> same way SQL:1999 does.

The current SQL standard *supersedes* all previous ones. There isn't
a hierarchy in the sense of "higher levels of compliance" that our
docs implicitly and falsely assume in many spots, and we need to make
them stop including this idea.

The only standard actually worth citing today is SQL:2008, and the day
the next one comes out, we need to change all our references to cite
it.

Cheers,
David.
--
David Fetter <david(at)fetter(dot)org> http://fetter.org/
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