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

From: Srinivasan Vasan <Vasan.Srinivasan_at_churchill.com>
Date: Thu, 8 Jul 2004 13:12:32 +0100
Message-ID: <4661DD1EF5C4EF4B9D2BCE3A3E52EF3304C321B0@brcexm04.churchill.com>

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(*)

---

         1

SQL> select count(null) from dual;

COUNT(NULL)

---

          0

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 - 07:09:15 CDT