Re: except command
| От | olivier.boissard@cerene.fr |
|---|---|
| Тема | Re: except command |
| Дата | |
| Msg-id | 46C0D794.3020105@cerene.fr обсуждение исходный текст |
| Ответ на | Re: except command ("Kevin Grittner" <Kevin.Grittner@wicourts.gov>) |
| Список | pgsql-admin |
Yes I noticed It was not an ANSI sql operator I think it's a good solution to spare temporay tables or result set I was searching a way to ease some réplication scripts but I don't think it will help me. It's better to use it to get a couple of records inside complex queries from many tables . Thanks for help Olivier Kevin Grittner a écrit : >>>> On Mon, Aug 13, 2007 at 4:30 PM, in message <46C0CD72.5090407@cerene.fr>, >>>> > "olivier.boissard@cerene.fr" <olivier.boissard@cerene.fr> wrote: > >> So it's like a filter on the first query >> > > Exactly; I think that sums it up better than anything I said. > > By the way, it does strike me as an odd omission that there is no set > operator in the ANSI standard to get you directly to the set of disjoint > elements. With two datasets, a and b, you could always get there with: > > (a EXCEPT b) UNION ALL (b EXCEPT a) > > or with: > > (a UNION ALL b) EXCEPT (a INTERSECT b) > > Of course, you could store the sets in temporary tables to get there without > generating from scratch each time, if that is expensive. > > -Kevin > > > > >
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