Re: Performance question

These answer to your question is that performance of queries is specific to the techniques used by the optimizer. Different relational DBMS engines use different optimization techniques. Over time, the optimizer in any given product evolves from one release of the product to the next.

For Oracle RDBMS and Oracle RDB, the only two I know, the exists construct will deliver better results.
(assuming you use cost based optimization with Oracle RDBMS)

Oracle RDBMS underwent significant changes to its optimizer between version 7 and version 8.

idiot wrote in message <3874a09e_at_athene.hdm-stuttgart.de>...
>I'm confused of using two methods of corellating the subquery, i. e.
>" ... x in (select y ...) ... " and
>" ... exists (select * .... where y = x) ... "
>
>is that a fact that one of them always works faster than other or there are
>nuances?
>
>thanx
>
>
>
Received on Thu Jan 06 2000 - 00:00:00 CET