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Subject: RE: IN or Exists --- performance issue
Hi Listers
I have a unique performance problem. As a general
rule by oracle while
writing SQL scripts EXISTS should be used in place
of IN.
As a general rule there is no general rule. Why do you want to use EXISTS if it goes
e recipients of list ORACLE-LSubject: IN or
Exists --- performance issue
Hi Listers
I have a unique performance problem. As a
general rule by oracle while writing SQL scriptsEXISTS should be used in
place of IN.
I'm having 2 sql for comparison using IN and
EXISTS operators.
With
Hi Listers
I have a unique performance problem. As a
general rule by oracle while writing SQL scriptsEXISTS should be used in
place of IN.
I'm having 2 sql for comparison using IN and
EXISTS operators.
With IN operator
SELECT /*+ PUSH_SUBQ USE_NL (a) INDEX (a) */
COUNT(1)
FROM mam_assets a
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Date: 2003/06/03 Tue AM 06:59:52 EDT
To: Multiple recipients of list ORACLE-L [EMAIL PROTECTED]
Subject: IN or Exists --- performance issue
Hi Listers
I have a unique performance problem. As a general rule by oracle while
writing SQL scripts EXISTS should be used in place of IN.
I'm
Munish,
You are right, as a *general rule of thumb* EXISTS is *usually* faster than
IN..
There can however be problems when an EXISTS is used to manipulate or select
data from a very large table, where the row exists in a far smaller table,
as it will read every row in the large table, and then
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Munish
I've got a funny feeling that this thing about using EXISTS rather than IN
is a bit of a myth. I do a lot of this sort of thing and I find that almost
invariably, an IN with a simple subquery is faster
Hi Listers
I have a unique performance problem. As a general
rule by oracle while
writing SQL scripts EXISTS should be used in place
of IN.
As a general rule there is no general rule. Why do you want to use EXISTS if it goes
faster with IN ?
EXISTS is mostly used with a correlated
