Re: [SQL] optimizing 2-table join w/millions of rows

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От Herouth Maoz
Тема Re: [SQL] optimizing 2-table join w/millions of rows
Дата
Msg-id l03110700b27da28b94ff@[147.233.159.109]
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Ответ на optimizing 2-table join w/millions of rows  (Michael Olivier <molivier@yahoo.com>)
Список pgsql-sql
At 4:26 +0200 on 20/11/98, Michael Olivier wrote:


>
> select U.acctname from usertest U, bgndtest B where
>     B.part_needed=3 and B.loc_needed=5 and
>     B.acctname=U.acctname and U.acctname in
>         (select acctname from usertest where part=2 and loc=3)

Can you explain *verbally* what you meant to do here? It seems as if the
subselect is redundant. How about:

SELECT U.acctname
FROM   usertest U, bgndtest B
WHERE  B.acctname = U.acctname
  AND  B.part_needed=3 AND B.loc_needed=5
  AND  U.part=2 AND U.loc=3;

Herouth

--
Herouth Maoz, Internet developer.
Open University of Israel - Telem project
http://telem.openu.ac.il/~herutma



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