What about using an outer join instead? This requires PostgreSQL 7.1 or later.
SELECT DISTINCT dom_ns.domname, dom_ns.tldtype
FROM dom_ns LEFT OUTER JOIN domains ON dom_ns.domname = domains.domname
WHERE domain.domname IS NULL;
--Wes Sheldahl
"Arsalan Zaidi" <azaidi%directi.com@interlock.lexmark.com> on 11/19/2001
05:31:43 AM
To: pgsql-general%postgresql.org@interlock.lexmark.com
cc: (bcc: Wesley Sheldahl/Lex/Lexmark)
Subject: [GENERAL] nested select query take too long
Hi.
The following query takes absolutely *ages* to run. Even with just a 1000
records in each table. It seems to me that the nested query is being run for
*every* value in the dom_ns table.
SELECT DISTINCT dom_ns.domname, dom_ns.tldtype FROM dom_ns WHERE
dom_ns.domname NOT IN (SELECT domname FROM domains WHERE domname IS NOT
NULL);
Why should is this happening? I just want the nested query to run once!
Thanks in advance.
--Arsalan.
-------------------------------------------------------------------
People often hate those things which they do not know, or cannot understand.
--Ali Ibn Abi Talib (AS)
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