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cost based optimizer [message #64862] Fri, 20 February 2004 22:00 Go to next message
ora
Messages: 47
Registered: June 2002
Member
Hi,

I want to know that if the optimizer mode is set to COST then is the order of tables and order of conditions in a join query matters or not?

Means, consider the following query:

select t1.* from t1,t2,t3
where
t1.c1 = t2.c1
and t2.c1 = t3.c1

In above query, if the optimizer mode is COST so the order of t1,t2,t3 and the order of conditions in "where" clause matters or not?
Re: cost based optimizer [message #64863 is a reply to message #64862] Fri, 20 February 2004 22:12 Go to previous messageGo to next message
Manish Thawani
Messages: 6
Registered: April 1998
Junior Member
Order of table or where cluase doesn't matter.
Re: cost based optimizer [message #64864 is a reply to message #64862] Fri, 20 February 2004 22:21 Go to previous message
Manish Thawani
Messages: 6
Registered: April 1998
Junior Member
Run a expalin Plan and see if you see any difference when order is changed and share the result with all in the message board.
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