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Message Posted: Wed, 13 Feb 2002 @ 14:22:57 GMT


     
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Subj:   Re: optimiser query
 
From:   John K. Wight

Just an observation from your reply David.

When you are dealing with INNER JOINS (of either the ANSI or WHERE clause way) and the order of tables in the from clause 'not normally sensitive'. This is true only for INNER JOINS as they are commutative and associative in the algebra. However, when you are doing OUTER joins, the order of the joins and ON clauses is important as OUTER joins are usually not commutative or associative. There is a good description of this in the DML manual on outer joins.

Just not aware if everyone in the TDADA 'room' was aware of that. Just and FYI.



     
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