----- Original Message -----
Sent: Monday, March 31, 2003 2:38
PM
Subject: Re: index ??
Sorry, forgot to ask the first time. What is the
selectivity of B?
At 12:53 PM 3/31/2003 -0800, you wrote:
>well , at A is not null and pt present there is only one distinct
value in A.
>
>ak
>----- Original Message -----
>From: <mailto:[EMAIL PROTECTED]>Wolfgang
Breitling
>To: <mailto:[EMAIL PROTECTED]>Multiple
recipients of list ORACLE-L
>Sent: Monday, March
31, 2003 10:34 AM
>Subject: Re: index ??
>
>What is the selectivity of
column A? How many distinct values? Is A
>nullable?
How many rows and blocks in the table and what are the nr of leaf
>blocks and the clustering factors of the indexes?
>
>At 09:08 AM 3/31/2003 -0800,
you wrote:
>
> >I
have a table X with unix index on column A ,B and non unique index on
> >A,C,D . The query give below doesn't use any
index .
> >
> >I
thought its due to function nvl being used here , so made a change
in
> >query to replace
> >
> >B = NVL(:b2,B)
with (B=:b2 or :b2 is null ) , but this one also not
> >using index . Why if I put an or condition it
doesn't use index while if I
> >put and
condition it will used ?
> >
> >IS there any way I can change query or index so that it starts
using index
> >( in a better way )
> >
> >
> >
> >Thanks,
> >
> >-ak
> >
> >
> >
> >
> >
> >
> >
> >SELECT z
> >
> >FROM
> >
> >X
> >
> >WHERE
> >
> >A = :b1 AND
> >
> >B = NVL(:b2,B) AND
> >
> >C= nvl(:b3,C)
And
> >
>
>D=nvl(:b4,D)
> >
> >
> >
> >
> >
> >
>
>Wolfgang Breitling
>Centrex Consulting
Corporation
><http://www.centrexcc.com>http://www.centrexcc.com
>
>
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