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>.