[ Sorry for slow response, I've been out of town ]
"Robert J. Sanford, Jr." <rsanford@nolimitsystems.com> writes:
> [ some questions already ably answered by Josh and Stephan ]
I just wanted to throw in one more tidbit:
> for example, one thing that one of my friends said is:
> select X
> from big_table
> ,little_table
> Generally speaking, Oracle optimizes better
> when the smaller/reducing tables are on the
> bottom and the larger tables are on the top.
> I believe SQLServer likes them in the opposite
> direction.
Postgres absolutely does not care: the optimizer will always consider
both A-join-B and B-join-A orders for every join it has to do. As
Stephan and Josh noted, you can constrain the join pairs the optimizer
will consider if you use explicit-JOIN syntax --- but each pair will be
considered in both directions.
regards, tom lane
