Re: [GENERAL] Problem about pgsql's column alias

Peter Eisentraut <peter_e(at)gmx(dot)net> writes:
> Tom Lane writes:
>> AS is not optional in Postgres, and will never be so unless we choose to
>> drop support for postfix operators, which I consider an unlikely choice.

> Well, we could drop the support for postfix operators in aliasing clauses
> that omit the AS.

I think it would be a bad idea in any case; it would mask errors too
easily. For example, you meant to say "SELECT a + b, ..." but wrote
"SELECT a b, ...". Or how about this:
SELECT 'foo'::character varying
Is "varying" an alias or part of the type name?

We've recently seen at least one comparable case where someone
unintentionally wrote what looked to the parser like a FROM-clause
alias, and was mystified at the behavior (I forget the details, but it
was just a week or two back). Omitting AS in FROM-clauses is tolerable
because the possible syntax in that area is fairly restricted, but I
think the spec authors were just plain foolish to allow it in the SELECT
targetlist.

regards, tom lane