Re: Problem using set-returning functions

Markus Schaber <schabi(at)logix-tt(dot)com> writes:
> navteq=# select foo,generate_x(bar) from test;
> ERROR: set-valued function called in context that cannot accept a set
> CONTEXT: PL/pgSQL function "generate_x" line 5 at return next

plpgsql SRFs don't support being called from the SELECT target list,
only from a FROM-expression. Your other function is probably written
in SQL not plpgsql; SQL functions do support this.

plpgsql could probably be fixed if we were really motivated to do so,
but I think most people who have looked at it feel we should phase out
the capability to call SRFs from a target list, rather than extend it.
It's weird and not very semantically sound --- in particular, there's no
very sensible definition if there's more than one of them in the target
list. See past discussions in the PG archives.

regards, tom lane