Re: Unions and where optimisation

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От Tomasz Myrta
Тема Re: Unions and where optimisation
Дата
Msg-id 3E1C366B.5080406@klaster.net
обсуждение исходный текст
Ответ на Unions and where optimisation  (Boris Klug <boris.klug@control.de>)
Ответы Re: Unions and where optimisation  (Boris Klug <boris.klug@control.de>)
Re: Unions and where optimisation  (Hannu Krosing <hannu@tm.ee>)
Список pgsql-performance
Hannu Krosing wrote:

>
> try making the orderevents view like this:
>
> create view orderevents as
> select rk.aufnr, sub.ts
>   from rk150 rk,
>      ( select ts from rk150 where aufnr = rk.aufr
>        union
>        select ts from rk151 where aufnr = rk.aufr
>        union
>        select ts from rk152 where aufnr = rk.aufr
>      ) as sub
> ;
>
> this could/should force your desired behavior.
>

Hannu, does it work?
Few months ago I lost some time trying to create this kind of query and
I always got error, that subselect doesn't knows anything about upper
(outer?) table.

In this query you should get error:
"relation rk does not exist".

What version of postgres do you have?
Tomasz Myrta


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