Re: Do I just not understand count()?
От | Ben |
---|---|
Тема | Re: Do I just not understand count()? |
Дата | |
Msg-id | Pine.LNX.4.30.0204081303290.9115-100000@gilgamesh.eos.SilentMedia.com обсуждение исходный текст |
Ответ на | Re: Do I just not understand count()? ("Nigel J. Andrews" <nandrews@investsystems.co.uk>) |
Список | pgsql-general |
This is the first time I've tried. I noticed that I could add a DISTINCT clause to count(), and wondered why I couldn't add an equality and make it work as well. On Mon, 8 Apr 2002, Nigel J. Andrews wrote: > > > Perhaps it would clear up things for those more expert on SQL [and it's > variations across DBs] than I if you could say on what system you would > normally do this. > > > > > That's what I'd normally do to, but in this case I want to run a query > > > more like > > > > > > select count(a=1), count(a=2) from t > > > > > > > > If I have the table t defined as: > > > > > > > > > > a > > > > > --- > > > > > 1 > > > > > 1 > > > > > 2 > > > > > > > > > > > > > > > and I say: > > > > > > > > > > select count(a=1) from t; > > > > > > > > > > should it give me 1 or 2 as a result? I'm getting 2, and I'd think I > > > > > should get 1.... > > > > > > > > > -- > Nigel J. Andrews > Director > > --- > Logictree Systems Limited > Computer Consultants > > > > ---------------------------(end of broadcast)--------------------------- > TIP 5: Have you checked our extensive FAQ? > > http://www.postgresql.org/users-lounge/docs/faq.html >
В списке pgsql-general по дате отправления: