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RE: index on null column

From: Jamadagni, Rajendra <Rajendra.Jamadagni_at_espn.com>
Date: Fri, 28 Mar 2003 05:08:36 -0800
Message-ID: <F001.005751CB.20030328050836@fatcity.com>


Here is an idea ...

Create a function that returns NULL if the value is null or any other acceptable value that can be ignored. And the function should return valid values otherwise. Then create a function based index on this and see if that helps you.

To put in other words, you are merely indexing a subset of rows that match your criteria, while ignoring others that you don't want to deal with.

Raj



Rajendra dot Jamadagni at espn dot com
Any views expressed here are strictly personal. QOTD: Any clod can have facts, having an opinion is an art !!

-----Original Message-----
Sent: Thursday, March 27, 2003 9:34 PM
To: Multiple recipients of list ORACLE-L

AK

   Yes, it will benefit the non-null records. Just remember that the null values aren't indexes.

Dennis Williams
DBA, 40%OCP, 100% DBA
Lifetouch, Inc.
dwilliams_at_lifetouch.com

-----Original Message-----
Sent: Thursday, March 27, 2003 5:19 PM
To: Multiple recipients of list ORACLE-L

I have a table with column A. there are 1000000 records in table out of which 500o records has not null in column A rest are null. if i created an index on A, will it benefit .  

thanks,
ak

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Author: DENNIS WILLIAMS
  INET: DWILLIAMS_at_LIFETOUCH.COM

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Author: Jamadagni, Rajendra
  INET: Rajendra.Jamadagni_at_espn.com

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Received on Fri Mar 28 2003 - 07:08:36 CST

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