query question

Silly question (and just because I would like to know exactly why):

This query:
select distinct x, y
from table1 t
join table2 t2
using (col1)
order by x;

is *slower* than this query:

select disting x, y
from table1
where col1 = (select col1 from table2)
ORDER BY x;

Is this because in the latter case the select col1 is cached?

Ooo, I would love to have a web page full of these tidbits (along with how
to get around the max and min aggregates and why as an example..., etc.)!

Thanks,

--
Laurette Cisneros
The Database Group
(510) 420-3137
NextBus Information Systems, Inc.
www.nextbus.com
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There is more to life than just SQL.