Re: self join revisited

From: Tom Lane
Subject: Re: self join revisited
Date: ,
Msg-id: 7884.1238606350@sss.pgh.pa.us
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In response to: self join revisited  (Rikard Pavelic)
Responses: Re: self join revisited  (Rikard Pavelic)
List: pgsql-performance

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self join revisited  (Rikard Pavelic, )
 Re: self join revisited  (Matthew Wakeling, )
 Re: self join revisited  (Tom Lane, )
  Re: self join revisited  (Rikard Pavelic, )
   Re: self join revisited  (Robert Haas, )

Rikard Pavelic <> writes:
> It would be great if Postgres could rewrite this query

AFAICS those queries are not going to produce the same results,
so Postgres would be 100% incorrect to rewrite it like that for you.

(If they do produce the same results, it would depend on a bunch
of assumptions you have not stated.)

            regards, tom lane


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