Marc,
> Basically, from how everyone has explained it, the ORDER BY will be done
> after all the JOINs are done, and the "product of the joins" are
> complete ... for it to be performed on a field not in the SELECT <field>
> clause, then those fields have to be "loaded into memory", *then*
> ORDERed, and then the query would return teh result set out of those
> "mega table" ...
Pretty much, yes. We have to load the referenced rows anyway because
that's the only way to locate visibility information, which is critical
for an inner join.
However, this discussion doesn't really belong on -hackers. Why don't you
bring it over to IRC?
--
--Josh
Josh Berkus
Aglio Database Solutions
San Francisco