Re: Query optimization path

"Bruno Wolff III" <bruno@wolff.to> wrote in message
news:20030112170108.GB31080@wolff.to...
>   Gaetano Mendola <mendola@bigfoot.com> wrote:
> > Hi all,
> >
> > I have the following query:
> >
> > SELECT count(1)
> > FROM providers p JOIN class_default cd    USING (id_provider)
> >                  JOIN user_data     ud    USING (id_class)
> >                  JOIN v_user_traffic ut   USING (id_user)
> > WHERE id_user_status in (4,5) AND
> >       p.company = 'XXXXX';
> >
> > is not slow but I notice that if I do explain analyze with the table
> > reordered
> > inside the select in another way the cost change.

> Using "JOIN" fixes the order that tables are joined in. If you are
> just doing inner joins, then you probably don't want to use the "JOIN"
> keyword. The exception being when there are so many tables being joined
> that you want to manually specify at least some of the join ordering in
> order to help out the planner.

And where is written this behavior ? Is it SQL standard ?


Ciao
Gaetano.