Oracle-L: Re: Do you ever have days where you dont want to think ?

From: <Jared.Still_at_radisys.com>
Date: Fri, 17 May 2002 14:53:29 -0800
Message-ID: <F001.00463DA6.20020517145329@fatcity.com>

Yeah, I have those days.

The beach sounds good; don't worry, I'll go find my own.

Wouldn't want to frighten the natives.

Try 'not exists', 'not in' forces a table scan.

Even better, use an explicit anti-join.

select a.f1, a.f2, a.f3, a.f4
from table1 a, table2 b
where a.f1 = b.n1(+)
and b.n1 is null;

I learned this from Larry Elkins, I *think* I did it properly.

Rather clever I thought.

Jared

"Johnson, Michael " <Michael.Johnson_at_oln-afmc.af.mil> Sent by: root_at_fatcity.com
05/17/2002 02:23 PM
Please respond to ORACLE-L

        To:     Multiple recipients of list ORACLE-L <ORACLE-L_at_fatcity.com>
        cc: 
        Subject:        Do you ever have days where you dont want to think ?

I just just wanna go lie on a beach naked on some remote island far far away and not think of anything for a month.

Here is the issue.....

I have a query that looks like this ...

select a.f1, a.f2, a.f3, a.f4 from table1 a where a.f1 not in
( select b.n1 from b );

there is a primary key index on b.n1
there is a concatenated primary key index on a.f1,a.f2,a.f3 there is a non-unique index on a.f1

the query shows that the index is being used on table b, but no indexes are being used on table a.

Mike
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Author: Johnson, Michael
INET: Michael.Johnson_at_oln-afmc.af.mil

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Author:
INET: Jared.Still_at_radisys.com

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