Alvaro Herrera <alvherre@commandprompt.com> writes:
> So is this the right way to approach the problem, or am I missing some
> simpler way?
See discussions of NikhilS's patch last year. I think the conclusion we
had arrived at was that we should refactor the representation of SubLink
so that a single-row subselect could be responsible for producing the
values of more than one Param (located in more than one place in the
query's expression trees). Otherwise you get into having to redefine
the representation of targetlists, which will break more code than is
pleasant to think about.
regards, tom lane