Re: 9205 Query behavior

From: Wolfgang Breitling <breitliw_at_centrexcc.com>
Date: Mon, 17 May 2004 09:42:34 -0600
Message-Id: <6.1.0.6.2.20040517093810.02b061b8@pop.centrexcc.com>

I wonder what kind of optimizer bug it is. I tried various hints, even RULE !, to no avail. However, adding rownum to the innermost sql produces the expected result:

SQL> l

1 select distinct deptno from ( select rownum, deptno, job, 2* min(sal) from scott.emp group by rownum, deptno, job) SQL> / DEPTNO

         10
         20
         30

3 rows selected.

SQL> l

1 select * from ( select distinct deptno from ( select rownum, deptno, job, 2* min(sal) from scott.emp group by rownum, deptno, job) where deptno = 20 ) SQL> / DEPTNO

1 row selected.

That seems to indicate some unnesting related error. However, using no_unnest hints does not change the behaviour.

At 03:55 PM 5/16/2004, you wrote:
>On 9205 database, load $OH/admin/utlsampl.sql
>
>run following query ... and observe ...
>
>set feedback on
>prompt Step 1
>select deptno, job, min(sal) from scott.emp group by deptno, job
>/
>prompt Step 2
>select distinct deptno from ( select deptno, job, min(sal) from
>scott.emp group by deptno, job ) where deptno = 20
>/
>prompt Step 3
>select * from ( select distinct deptno from ( select deptno, job,
>min(sal) from scott.emp group by deptno, job ) where deptno = 20 )
>/

regards

Wolfgang Breitling
Centrex Consulting Corporation
www.centrexcc.com

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Received on Mon May 17 2004 - 10:41:10 CDT