Re: A fine point about OUTER JOIN semantics

From: Thomas Lockhart <lockhart(at)alumni(dot)caltech(dot)edu>
To: Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us>
Cc: pgsql-hackers(at)postgreSQL(dot)org
Subject: Re: A fine point about OUTER JOIN semantics
Date: 2000-09-05 14:29:22
Message-ID: 39B50342.69108852@alumni.caltech.edu
Views: Raw Message | Whole Thread | Download mbox | Resend email
Thread:
Lists: pgsql-hackers

> Well, I guess so, but I can't get excited about adding machinery to
> detect cases like this ... are there any less-silly examples that make
> a more compelling case for expending planner cycles to see if an outer
> join can be reduced to an inner join?

Well, in all cases the outer join reduces to an inner join if there is a
qualification which would eliminate nulls from any intermediate result.
It would be neat to see this happen automagically, but perhaps that
would be a gratuitously studly feature ;)

- Thomas

In response to

Browse pgsql-hackers by date

  From Date Subject
Next Message Leandro Fanzone 2000-09-05 14:41:23 C++ library probs
Previous Message Tom Lane 2000-09-05 13:57:01 Re: Important 7.0.* fix to ensure buffers are released