Re: request for sql3 compliance for the update command

On Thu, 20 Feb 2003, Kevin Brown wrote:

> Tom Lane wrote:
> > UPDATE totals SET
> > xmax = ss.xmax, xmin = ss.xmin, ...
> > FROM
> > (SELECT groupid, max(x) AS xmax, ... FROM details GROUP BY groupid) ss
> > WHERE groupid = ss.groupid;
>
> As long as any individual item that you can express in the
> parenthesized (Informix) syntax can also be expressed as an element in
> a SELECT, then the above is equivalent in every way to the Informix
> syntax. And since SELECT allows subselects, it seems to me that the
> PG syntax is complete.
>
> My question is whether or not there's likely to be an approved
> standard way of accomplishing what either syntax does. Is there
> anything in the current draft that addresses this?

Yes there is. I've posted the URL on the hackers list a while back, but
here it is again:

ftp://sqlstandards.org/SC32/WG3/Progression_Documents/FCD/4FCD1-02-Foundation-2002-01.pdf

pp 851 to 862, in particular, p 858 defines the the <set clause list> as
supporting <multiple column assignment> as supporting something like:

(target1, target2, target3) = (value1, value2, value3)