Re: tune between query/join
From: Gints Plivna <gints.plivna_at_gmail.com>
Date: Fri, 21 Oct 2011 12:27:13 +0300
Message-ID: <CAN2wOq1RnobUas2QUjTMF5HD+Z3Gpzv=v1X7juzQ-_JuJpeH_w_at_mail.gmail.com>
2011/10/21 David Fitzjarrell <oratune_at_yahoo.com>:
> The original 'join' produces useless noise along with some valid data buried deep within.
Date: Fri, 21 Oct 2011 12:27:13 +0300
Message-ID: <CAN2wOq1RnobUas2QUjTMF5HD+Z3Gpzv=v1X7juzQ-_JuJpeH_w_at_mail.gmail.com>
2011/10/21 David Fitzjarrell <oratune_at_yahoo.com>:
> The original 'join' produces useless noise along with some valid data buried deep within.
As we don't know the OPs original problem it is hard to say whether it
is useless noise or valuable solution FOR HIM.
Generally join doesn't mean only eaquality, join predicate can be
everything not only (=) meaning equi join, but also any other
condition. How necessary and appropriate it is in this case of course
is another question.
And yes - if you have anything other than equi join, then the only
solution for actual join mechanism remains either nested loops
(generally not good for big datasets) or merge join. Hash joins are
possible only if there is equality and respectively hashes to compare.
Gints Plivna
http://www.gplivna.eu
-- http://www.freelists.org/webpage/oracle-lReceived on Fri Oct 21 2011 - 04:27:13 CDT