Tom Lane wrote: > Alvaro Herrera <[EMAIL PROTECTED]> 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.
Yeah, I agree we should disallow it. For the curious, the bizarre behavior is alvherre=# update pk set id = count(id) ; ERROR: ctid is NULL alvherre=# update pk set id = sum(id) ; ERROR: ctid is NULL Clearly not a very useful error message. > 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. I refrain -- tried following it but I don't know that code at all. -- Alvaro Herrera http://www.CommandPrompt.com/ The PostgreSQL Company - Command Prompt, Inc. ---------------------------(end of broadcast)--------------------------- TIP 3: Have you checked our extensive FAQ? http://www.postgresql.org/docs/faq
