RE: select with Null

From: Gogala, Mladen <MGogala_at_oxhp.com>
Date: Mon, 27 Nov 2000 10:16:53 -0500
Message-Id: <10693.122947@fatcity.com>

Unless we are talking 8i and function based indexes, that query doesn't use indexes, neither before nor after the full scan.

-----Original Message-----

From: Natasha Batson [mailto:nbatson_at_neal-and-massy.com] Sent: Wednesday, November 22, 2000 2:31 PM To: Multiple recipients of list ORACLE-L Subject: Re: select with Null

Clarify something for me please:

Nulls are not stored in an index.

So the query :

select d.discount_type

from discount d
where (NVL(d.company_code,'XX') = 'XX')

and (NVL(d.operator_code,'YY') = 'YY')\

will first perform a full table scan to find the nulls and then utilise the index to locate the values?

Original Message ----- To: "Multiple recipients of list ORACLE-L" <ORACLE-L_at_fatcity.com> Sent: Wednesday, November 22, 2000 2:15 PM

select d.discount_type

from discount d
where (NVL(d.company_code,'XX') = 'XX')

and (NVL(d.operator_code,'YY') = 'YY')

Raj Gopalan <raj.gopalan_at_netdecisions.co.uk> on 22/11/2000 12:35:24 PM

Please respond to ORACLE-L_at_fatcity.com

 To:      Multiple recipients of list ORACLE-L
          <ORACLE-L_at_fatcity.com>

 cc:      (bcc: Marcos Vera/M&S Consultores/51)

Subject: select with Null

Hello list,

I have a query

select d.discount_type

from discount d
where (d.company_code = 'XX' or

            d.company_code is null)
     and (d.operator_code = 'YY' or
             d.operator_code is null)

Apparently, oracle is not using the index since I am using IS NULL. But the functional requirement is such that the query need to consider records even if company_code, Operator_code ,... is null.

Any thoughts on how do I modify this query so that the index is being used.

TIA Raj
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Author: Raj Gopalan
INET: raj.gopalan_at_netdecisions.co.uk

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Author: Natasha Batson
INET: nbatson_at_neal-and-massy.com

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