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

From: Mladen Gogala <mladen_at_wangtrading.com>
Date: Thu, 8 Jul 2004 10:31:52 -0400
Message-ID: <20040708143152.GM17716@mladen.wangtrading.com>

On 07/08/2004 09:40:17 AM, Peter Miller wrote:
> 1,749,951 rows returned in every case
>
> count(rowid) - approx 3.2 secs
> count(obj#) - approx 3.5 secs
> count(1) - approx 3.6 secs
> count(*) - approx 3.6 secs
> count(rownum)- approx 4.6 secs
> count(source)- approx 8.6 secs
>

Connected to:
Oracle9i Enterprise Edition Release 9.2.0.5.0 - Production With the Partitioning option
JServer Release 9.2.0.5.0 - Production

SQL> set timing on
SQL> select count(*) from wi_cumulative;

COUNT(*)

12148659

Elapsed: 00:00:20.16
SQL> select count(rowid) from wi_cumulative;

COUNT(ROWID)

12148659

Elapsed: 00:00:20.62
SQL> select count(1) from wi_cumulative;

COUNT(1)

12148659

Elapsed: 00:00:21.52
SQL> select count(null) from wi_cumulative;

COUNT(NULL)

Elapsed: 00:00:19.12
SQL> Tanel's favorite way of counting differed from the real count for only about 12 million rows, and it wasn't that much faster, so the difference doesn't justify lack of precision.

-- 
Mladen Gogala
Oracle DBA



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Received on Thu Jul 08 2004 - 09:28:45 CDT