Am Mittwoch, 26. Juli 2006 22:58 schrieb Tom Lane:
> The reason people want this syntax is that they expect to be
> able to write, say,
>
> UPDATE mytab SET (foo, bar, baz) =
> (SELECT alpha, beta, gamma FROM othertab WHERE key = mytab.key);
I don't find any derivation in the standard that would permit this. The only
thing I could find are variations on
SET (a) = x -- no parentheses
SET (a, b) = (x, y)
SET (a, b) = ROW (x, y)
where x and y are some sort of value expression. I would have expected the
sort of thing that you describe, but if you know how to derive that, I'd like
to see it.
--
Peter Eisentraut
http://developer.postgresql.org/~petere/