From: Simon Riggs <simon@2ndquadrant.com>
To: Matthew Wakeling <matthew@flymine.org>
Cc: pgsql-performance <pgsql-performance@postgresql.org>
Subject: Re: Outer joins and equivalence
Date: Wed, 28 May 2008 14:39:10 +0100
Message-ID: <1211981950.4489.473.camel@ebony.site> (raw)
In-Reply-To: <Pine.LNX.4.64.0805281144200.16756@aragorn.flymine.org>
References: <1211918358.4489.257.camel@ebony.site>
<Pine.LNX.4.64.0805281144200.16756@aragorn.flymine.org>
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 (a.id = c.id) LEFT JOIN C ON (b.id = c.id)
>
> 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 www.2ndQuadrant.com
PostgreSQL Training, Services and Support
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To: pgsql-performance@postgresql.org
Cc: simon@2ndquadrant.com, matthew@flymine.org
Subject: Re: Outer joins and equivalence
In-Reply-To: <1211981950.4489.473.camel@ebony.site>
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