Hi,
See below test. Count(*) is slowest by a large degree. Count of
constant is the fastest, count of pseudocolumn just slightly slower.
-Paul

Connected to Oracle9i Enterprise Edition Release 9.2.0.4.0

SQL> select count(*) from temp1;

COUNT(*)
----------
125222

Executed in 0.844 seconds

SQL> select count(1) from temp1;

COUNT(1)
----------
125222

Executed in 0.141 seconds

SQL> select count(rowid) from temp1;

COUNT(ROWID)
------------
125222

Executed in 0.188 seconds

-----Original Message-----
From: Mahapatra Himanshu (*IC)
[mailto:oracledba-ezmlmshield-x88730386.[Email address protected]
Sent: Thursday, September 06, 2007 9:54 AM
To: LazyDBA Discussion
Subject: RE: Count function

Count(2) will be faster as it does not need to read the entire block, as
"2" is a constant.

Thanks & Regards,
Himanshu Mahapatra

-----Original Message-----
From: Dindy Paul
[mailto:oracledba-ezmlmshield-x88365709.[Email address protected]
Sent: 06 September 2007 14:50
To: LazyDBA Discussion
Subject: RE: Count function

There is no difference.
There was a discussion recently where it seemed as if using count(rowid)
was a bit faster than other methods.
Paul D.

-----Original Message-----
From: Ajay Kumar Jindal
[mailto:oracledba-ezmlmshield-x7807713.[Email address protected]
Sent: Thursday, September 06, 2007 7:10 AM
To: LazyDBA Discussion
Subject: Count function

Dear All,

can anybody tell me what is the difference betweeen count(*) and
count(2)


Regards,
Ajay Jindal


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