Tom Lane wrote:
> Alvaro Herrera <alvherre@commandprompt.com> writes:
>> update pk set id = max(id) + 2;
>
> I'm fairly sure this query is illegal per spec. There are ancient
> discussions in the archives about whether aggregates in an UPDATE target
> list can have a consistent interpretation or not. We never found one,
> but never got around to disallowing it either. Maybe it's time. If you
> try it with something like sum() you don't get a crash, but you do get
> rather bizarre behavior.
On 8.x (7.4 and 7.3 as well) it will update "1" row :). On 8.1 and HEAD
it crashes. This has been verified on 32bit, 64bit x86 and PPC.
> Having said that, this may well expose a bug in the MAX-optimization
> code that has consequences for more useful queries. I'll take a look
> later today if no one beats me to it.
Sincerely,
Joshua D. Drake
>
> regards, tom lane
>
> ---------------------------(end of broadcast)---------------------------
> TIP 4: Have you searched our list archives?
>
> http://archives.postgresql.org
>
--
=== The PostgreSQL Company: Command Prompt, Inc. ===
Sales/Support: +1.503.667.4564 || 24x7/Emergency: +1.800.492.2240 Providing the most comprehensive PostgreSQL
solutionssince 1997 http://www.commandprompt.com/
