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Re: join removal

Marko Tiikkaja <marko.tiikkaja@cs.helsinki.fi>

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From: Marko Tiikkaja <marko.tiikkaja@cs.helsinki.fi>
To: Pavel Stehule <pavel.stehule@gmail.com>
Cc: Robert Haas <robertmhaas@gmail.com>, Tom Lane <tgl@sss.pgh.pa.us>, Greg Stark <stark@mit.edu>, "<pgsql-hackers@postgresql.org>" <pgsql-hackers@postgresql.org>
Date: 2010-03-29T08:25:31Z
Lists: pgsql-hackers 
On 2010-03-29 11:19 +0200, Pavel Stehule wrote:
> postgres=# explain select  a from a left join b on true;

This is effectively a cross join and it would give wrong answers.  Try
SELECT a FROM a LEFT JOIN b ON a.a = b.b;


Regards,
Marko Tiikkaja