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Re: Outer joins and equivalence

From: Simon Riggs <simon(at)2ndquadrant(dot)com>
To: Matthew Wakeling <matthew(at)flymine(dot)org>
Cc: pgsql-performance <pgsql-performance(at)postgresql(dot)org>
Subject: Re: Outer joins and equivalence
Date: 2008-05-28 13:39:10
Message-ID: (view raw or whole thread)
Lists: pgsql-hackerspgsql-performance
On Wed, 2008-05-28 at 11:45 +0100, Matthew Wakeling wrote:
> On Tue, 27 May 2008, Simon Riggs wrote:
> > I do recognise that we would *not* be able to deduce this form of SQL
> >
> > A JOIN B ON ( = LEFT JOIN C ON ( =
> Surely that would not be valid SQL?

You are right, but my point was about inferences during SQL planning,
not about initial analysis of the statement.

 Simon Riggs 
 PostgreSQL Training, Services and Support

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