Subject RE: [ib-support] Correct method for joining tables
Author Stephen Wood
Thanks Set,

Thanks for the input, I understand what you are saying....I haven't timed
it, I was just sort of trying to guess what the engine does, but like you, I
also prefer having everything in the where clause for readability...

-----Original Message-----
From: Svein Erling Tysvaer [mailto:svein.erling.tysvaer@...]
Sent: 10 February 2003 13:11
Subject: RE: [ib-support] Correct method for joining tables

Hi again!

At 12:28 10.02.2003 +0200, you wrote:
>Hi Set,
>No, you are very wrong. If this was the case, then Fb would have to use
>Natural in its plans a whole lot more.
>I don't understand what you mean, if you specified a where clause using an
>indexed field, would it matter if it was in the "where" clause section or
>the "on" section of the join? If not, then it wouldn't need to do natural

What I tried to say was simply that if you select without any where clause
(i.e. any criteria that is not joining tables - regardless of where it is
specified), then at least one table have to be accessed in its natural
order. Joining tables first and thereafter take into account the where
criteria (again, regardless of where it is specified) would be inefficient,
and I do not believe Fb would done anything that way.


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