Thursday, July 15, 2004, 8:08:04 AM, Stephen.Lee@(protected) (Stephen.Lee@(protected)) wrote:
SLDC > I believe the purpose of the subquery was to "request
SLDC > it ". The function was being applied to data that was
SLDC > not in the subquery. If this is part of the laws of
SLDC > SQL processing, "then the law is an ass ". I 'm more
SLDC > inclined to say that this is a bug.
Stephen 's original problem and Tanel 's solution are
fascinating. I can see where the optimizer might try and
combine Stephen 's main query and subquery into just one query.
However, it seems to me that an optimization should *never*
return different results from the original operation that is
being optimized.
This begs the question of how the optimizer should decide
whether it 's safe to merge a subquery and main query.
Clearly, the optimizer seems to have made the wrong call
in the case of the query we 've been talking about.
I wish I had more time to spend thinking about all this, but
I 've got to get to work for the day.
Best regards,
Jonathan Gennick --- Brighten the corner where you are
http://Gennick.com * 906.387.1698 * mailto:jonathan@(protected)
Join the Oracle-article list and receive one
article on Oracle technologies per month by
email. To join, visit http://five.pairlist.net/mailman/listinfo/oracle-article,
or send email to Oracle-article-request@(protected) and
include the word "subscribe " in either the subject or body.
-- ---- ---- ---- ---- ---- ---- ---- ---- ---- ---- ---- ------
Please see the official ORACLE-L FAQ: http://www.orafaq.com
-- ---- ---- ---- ---- ---- ---- ---- ---- ---- ---- ---- ------
To unsubscribe send email to: oracle-l-request@(protected)
put 'unsubscribe ' in the subject line.
--
Archives are at http://www.freelists.org/archives/oracle-l/
FAQ is at http://www.freelists.org/help/fom-serve/cache/1.html
-- ---- ---- ---- ---- ---- ---- ---- ---- ---- ---- ---- ---- --
