| From: | Stephan Szabo <sszabo(at)megazone23(dot)bigpanda(dot)com> |
|---|---|
| To: | Patrick Welche <prlw1(at)newn(dot)cam(dot)ac(dot)uk> |
| Cc: | <pgsql-general(at)postgresql(dot)org> |
| Subject: | Re: trivial sql help |
| Date: | 2002-10-10 16:14:41 |
| Message-ID: | 20021010091100.C17293-100000@megazone23.bigpanda.com |
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| Thread: | |
| Lists: | pgsql-general |
On Thu, 10 Oct 2002, Patrick Welche wrote:
> update rawrequest
> set cid=(select pc.c
> from pers_comp as pc
> where pc.p=pid
> group by pc.c
> having count(pc.c)=1
> )
> where pr
> ;
>
> ERROR: More than one tuple returned by a subselect used as an expression.
>
> pid, pc.p, pc.c, cid are all integers. pc just has 2 columns p and c.
>
> I thought putting the count()=1 in there would force a single tuple..
No, that'll limit you only to groups having a count of 1. It'll still
give multiple groups. You could probably use limit to get 1 row, but
what's the actual behavior you want the update to have?
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