Vadim Mikheev <vadim(at)krs(dot)ru> writes:
> Tom Lane wrote:
>> For some reason we currently support sub-SELECT expressions only
>> in WHERE and HAVING clauses, not in the target list of a SELECT.
>> Does anyone know why this is?
> As usual, I just hadn't time to do more than it's done for
> 6.3.X -:) Subselects were not in my TODO list, I made base
> implementation because of there were many requests for them.
OK, I'll see about adding the missing transformations in the
planner. Shouldn't be hard.
> BTW, please don't forget subselects in FROM.
That seems to be a considerably bigger task :-(
regards, tom lane