Re: Is this JOIN good ?

From: Keith <keithhoxie_at_verizon.net>
Date: 16 Oct 2006 16:18:35 -0700
Message-ID: <1161040714.976307.82370@m73g2000cwd.googlegroups.com>

klabu wrote:
> Assuming you don't know anything about these 3 tables beyond FK & PK
>
> select *
> from A, B, C
> where A.fk = C.pk
> and B.fk = C.pk
>
> Is this JOIN "complete" ?
> or an additional predicate is needed between A and B ?
>
>
> thanks

Oracle is able to infer A.fk=B.fk if that is your question.

See "Transitive Closure" ch 6, pg 141 in "Cost Based Oracle Fundamentals" by Jonathan Lewis. Received on Mon Oct 16 2006 - 18:18:35 CDT