Re: Making the subquery alias optional in the FROM clause

On Mon, 27 Jun 2022 at 16:12, Julien Rouhaud <rjuju123(at)gmail(dot)com> wrote:
>
> It doesn't play that well if you have something called subquery though:
>
> [example that changes a user-provided alias]
>
> While the output is a valid query, it's not nice that it's replacing a
> user provided alias with another one (or force an alias if you have a
> relation called subquery).

It's already the case that user-provided aliases can get replaced by
new ones in the query-deparsing code, e.g.:

CREATE OR REPLACE VIEW test_view AS
SELECT x.a, y.b
FROM foo AS x,
(SELECT b FROM foo AS x) AS y;

\sv test_view

CREATE OR REPLACE VIEW public.test_view AS
SELECT x.a,
y.b
FROM foo x,
( SELECT x_1.b
FROM foo x_1) y

and similarly it may invent technically unnecessary aliases where
there were none before. The query-deparsing code has never been
alias-preserving, unless you take care to give everything a globally
unique alias.

Regards,
Dean