select user from dual - performance issue

From: Norman Dunbar <Norman.Dunbar_at_lfs.co.uk>
Date: Thu, 19 Jun 2003 11:55:25 +0100
Message-ID: <E2F6A70FE45242488C865C3BC1245DA703CF78C0@lnewton.leeds.lfs.co.uk>

I'm sure I saw an article on www.hotsos.com which mentioned performance problems with DUAL.

Cheers,
Norman.

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Norman Dunbar (at home on Linux)
Oracle_at_mssqlBountifulSolutions.co.uk

(Delete a Microsoft database name to reply - clue, mssql !)

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-----Original Message-----

From: uwe.wiedl_at_web.de (Uwe Wiedl) [mailto:uwe.wiedl_at_web.de] Posted At: Thursday, June 19, 2003 9:43 AM Posted To: server
Conversation: select user from dual - performance issue Subject: select user from dual - performance issue

DUAL table

got a query which uses the "select user from dual" statement.

select * from xy where name in (select user from dual) this is up to 10 times slower then

select * from xy where name = user

But this is not for every user in the database the case. Why ? Received on Thu Jun 19 2003 - 05:55:25 CDT