Oracle's update statement

Hi all,

I am trying to partially update a table based on a heavy query.

If I use following update:

update

        table_A
set

(ColA, ColB) =
(select ColA, ColB

	from heavy_query_B alias_B
	where id = table_A.id)
where
	exists


	(select *

	from heavy_query_B alias_B
	where id = table_A.id)

It would be extremely slow. The "where" clause is required to avoid updating unwanted rows in table_A, however i think it's one of the problems that impact performance.

Any idea that could help?

Thanks a lot! Received on Fri Nov 03 2006 - 10:52:26 CST