David Newall <[EMAIL PROTECTED]> writes:
> It's clearly an optimisation issue:

No, it's an outer-join-semantics issue.

> select * from a join b optimises differently to select * from a join
> (select * from b) as b

The above claim is provably false.  Now, if you throw in some more
tables and sprinkle in a LEFT JOIN instead of just JOIN here and there,
you can get different plans --- but the semantics are not necessarily
the same, either.

                        regards, tom lane

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