"Jonah H. Harris" <jonah(dot)harris(at)gmail(dot)com> writes:
> Not stupid, it doesn't work :) This was a limitation of the original
> design based on (IIRC) executor-related issues.
There are definitional issues not only implementation ones; in
particular, in subquery-like cases it's entirely unclear how many times
the DML operation will or should get evaluated.
regards, tom lane