Re: Making the subquery alias optional in the FROM clause

On Tue, 28 Jun 2022 at 00:32, Julien Rouhaud <rjuju123(at)gmail(dot)com> wrote:

> As to forcing SQL-complaint queries, that ship sailed a long time ago:
> > Postgres allows but does not enforce the use of SQL-compliant queries,
> and
> > many of its important features are extensions anyway, so forcing SQL
> > compliant queries is out of the question (although I could see the
> utility
> > of a mode where it warns or errors on non-compliant queries, at least in
> > principle).
>
> Sure, but it doesn't mean that we should support even more non-compliant
> syntax
> without any restraint. In this case, I don't see much benefit as it's not
> solving performance problem or something like that.
>

It's improving developer performance by eliminating the need to make up
utterly useless names. I don't care if behind the scenes names are
assigned, although it would be even better if the names didn't exist at
all. I just want the computer to do stuff for me that requires absolutely
no human judgement whatsoever.

> As to bad habits, I'm having trouble understanding. Why do you think
> > leaving the alias off a subquery is a bad habit (assuming it were
> allowed)?
>
> I think It's a bad habit because as far as I can see it's not supported on
> mysql or sqlserver.
>

So it’s a bad habit to use features of Postgres that aren’t available on
MySQL or SQL Server?

For myself, I don’t care one bit about whether my code will run on those
systems, or Oracle: as far as I’m concerned I write Postgres applications,
not SQL applications. Of course, many people have a need to support other
systems, so I appreciate the care we take to document the differences from
the standard, and I hope we will continue to support standard queries. But
if it’s a bad habit to use Postgres-specific features, why do we create any
of those features?

> If the name is never used, why are we required to supply it?
>
> But similarly, I many times relied on the fact that writable CTE are
> executed
> even if not explicitly referenced. So by the same argument shouldn't we
> allow
> something like this?
>
> WITH (INSERT INTO t SELECT * pending WHERE ts < now())
> SELECT now() AS last_processing_time;
>

I’m not necessarily opposed to allowing this too. But the part which causes
me annoyance is normal subquery naming.