Tom Lane wrote:
> Peter Eisentraut <peter_e@gmx.net> writes:
> > As previously mentioned, AS is already used by the SQL standard for
> > a different purpose in this context.
>
> Hm? [ reads spec ... ] Oh, you mean <generalized expression>.
> Does that actually do anything useful? It looks like it's just
> a random shortcut for a CAST expression in a parameter list.
I imagine that since a function call is the only place where the exact
type of a datum really matters and is also ambiguous in general (under
strict SQL rules, of course), they devised an abbreviated casting
syntax for it. In any case, we shouldn't use the syntax for something
else.
--
Peter Eisentraut
http://developer.postgresql.org/~petere/