Re: Where question

From: <michael_bialik_at_my-deja.com>
Date: Wed, 13 Oct 1999 20:59:16 GMT
Message-ID: <7u2rqs$asp$1@nnrp1.deja.com>

Hi.

If you are using RBO then it will use index. For CBO it will use the index as well assuming you have a non-trivial amount of data.
Use EXPLAIN to verify the index usage. You may use hints to "push" optimizer to use index : SELECT /*+ FIRST_ROWS */ *
FROM emp
WHERE emp_id = 'XXX' AND salary > 10000

SELECT /*+ index(emp) */ *
FROM emp
WHERE emp_id = 'XXX' AND salary > 10000

The order of fields does not matter.

HTH. Michael.

In article <3804A345.89870870_at_hotmail.com>, Mario Yepes <pafu_at_hotmail.com> wrote:
>
> --------------007269B43262A618446BA508
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>
> Hi !!
>
> I have an idiot question, suppose that I have a table with these
fields:
>
> empl_id, name, address, zipcode, salary
>
> And an index by empl_id, salary
>
> How I should use the where clause to "take or use" that index
>
> where empl_id = 'xxx'
> and salary > 10000;
>
> or
>
> where salary > 10000;
> and empl_id = 'xxx';
>
> Regards,
> Diego
>
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> <!doctype html public "-//w3c//dtd html 4.0 transitional//en">
> <html>
> Hi !!
> I have an idiot question, suppose that I have a table with these
fields:
> empl_id, name, address, zipcode, salary
> And an index by empl_id, salary
> How I should use the where clause to "take or use" that
index
> where empl_id = 'xxx'
>    and  salary > 10000;
> or
> where salary > 10000;
>    and empl_id = 'xxx';
> Regards,
> Diego</html>
>
> --------------007269B43262A618446BA508--
>
>

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Before you buy. Received on Wed Oct 13 1999 - 15:59:16 CDT