Re: Do I just not understand count()?

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Тема Re: Do I just not understand count()?
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Msg-id Pine.LNX.4.30.0204081303290.9115-100000@gilgamesh.eos.SilentMedia.com
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Ответ на Re: Do I just not understand count()?  ("Nigel J. Andrews" <nandrews@investsystems.co.uk>)
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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
>
>
>
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