RE: Difference between count(1) and count(*)

From: rob zijlstra <rmsah_at_xs4all.nl>
Date: Thu, 8 Jul 2004 14:21:16 +0200
Message-Id: <200407081221.i68CLOtc017727@smtp-out1.xs4all.nl>

Vasan,

Well, your question indicates that you don't have the right attitude to be an expert. The real question should be: 'How long will it take to ascertain that in your system count(null) has no meaning and so how long can I write bills?'

Rob Zijlstra

-----Original Message-----
From: oracle-l-bounce_at_freelists.org [mailto:oracle-l-bounce_at_freelists.org] On Behalf Of Srinivasan Vasan
Sent: donderdag 8 juli 2004 14:13
To: 'oracle-l_at_freelists.org'
Subject: RE: Difference between count(1) and count(*)

Hi! Tanel,

What exactly would we use a COUNT(NULL) for as it always returns 0?

Cheers,=20

Vasan.

-----Original Message-----
From: Tanel P=F5der [mailto:tanel.poder.003_at_mail.ee]=20 Sent: 08 July 2004 09:38
To: oracle-l_at_freelists.org
Subject: Re: Difference between count(1) and count(*)

I've actually seen an "expert" optimizing the count() statement, by = using
count(null) "since null means nothing and thus is the fastest" :)

But check this:

SQL> select count(*) from dual;

COUNT(*)

SQL> select count(null) from dual;

COUNT(NULL)

Tanel.

Original Message -----=20 From: "Jeremiah Wilton" <jwilton_at_speakeasy.net> To: <oracle-l_at_freelists.org> Sent: Thursday, July 08, 2004 9:31 AM Subject: Re: Difference between count(1) and count(*)

> > On Thu, 8 Jul 2004 11:27:28 +0530 oracle-l_at_freelists.org wrote:
> > > Can you let me know the difference between count(*) and count(1) =
?
> >
> > count(1) is supposed to be more efficient and faster.

>
> Oh boy, here we go.
>
> --
> Jeremiah Wilton
> http://www.speakeasy.net/~jwilton
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Received on Thu Jul 08 2004 - 07:18:02 CDT