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

From: Herouth Maoz <herouth(at)oumail(dot)openu(dot)ac(dot)il>
To: Michael Olivier <molivier(at)yahoo(dot)com>, "pgsql-sql postgresql(dot)org" <pgsql-sql(at)postgreSQL(dot)org>
Subject: Re: [SQL] optimizing 2-table join w/millions of rows
Date: 1998-11-22 11:18:03
Message-ID: l03110700b27da28b94ff@[147.233.159.109]
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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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