Re: Polymorphic arguments and composite types

On Fri, 5 Oct 2007, Simon Riggs wrote:

> On Fri, 2007-10-05 at 10:32 -0700, Stephan Szabo wrote:
> > On Fri, 5 Oct 2007, Simon Riggs wrote:
> >
> > > Because we already do exactly that here:
> > >
> > > select 1, (select col2 from c), 3;
> > >
> > > The inner select returns a ROW, yet we treat it as a single column
> > > value.
> >
> > The inner select does not return a row. It's not a <row subquery>, it's a
> > <scalar subquery>.
>
> Thanks Stephan, Tom already explained that.
>
> My comments above were in response to "Why would you think that?"

Right, but I guess I couldn't see why you would consider that the same as
treating a rowtype as a scalar, because when I look at that my brain
converts that to a scalar subquery, so I guess I simply see the scalar.
If we supported select 1, (select 2,3), select 4 giving something like
(1,(2,3),4), I'd also have confusion over the case, but that should error.