Re: problem in select

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От Richard Huxton
Тема Re: problem in select
Дата
Msg-id 200209131756.26359.dev@archonet.com
обсуждение исходный текст
Ответ на problem in select  ("frank_lupo" <frank_lupo@email.it>)
Список pgsql-general
On Friday 13 Sep 2002 5:32 pm, frank_lupo wrote:
> This selection is more fast in ingres vs postgres
> Ingres 6.4    0.04 sec
> Postgres 7.2  0.42 sec
> select titolo,id,anno from ircalend where anno=2002 and id in(select
> distinct(idcalend) from ircalend_3) order by anno,titolo
 because ?

Who knows? If you want people to help with this, you'll need to give them more
information. Things like the output of EXPLAIN SELECT ... and some details on
how many records are in each table would be a good start.

So, given that we don't have that I'd suggest looking to see if you can't
replace IN with EXISTS since PostgreSQL isn't very clever about IN. See mail
archives and manual for details. But look at the EXPLAIN readout first.

- Richard Huxton

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