Re: [PATCHES] extension for sql update

[Peter Eisentraut <peter_e(at)gmx(dot)net>]

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/