Re: Q: Performance
Date: 1995/06/02
Message-ID: <3qo9uh$u4k_at_caesar.ultra.net>#1/1
martinj_at_pi.net wrote:
>Hello,
>Because of daily usage of large tables, I have some performance questions I'd
>like answers to:
>1. What's faster:
>-----------------
>A. select rownum from A where A.field1 NOT IN
> (select fieldA from B)
>B. select rownum from A where NOT EXISTS
> (select 'x' from B where A.field1 = B.fieldA)
>C. Anything else
select rownum
from A A,
B B
where A.fieldA = B.fieldA (+)
and B.fieldA is null;
>2. Are there performance differences between:
>---------------------------------------------
>A. Select count(*) ...
>B. Select count(rownum) ...
>C. Select count('x') ....
A is the standard
>3. What's faster:
>-----------------
>A. Insert into ... values (....) as select ...
>B. Insert with a cursor
A SQL is almost always faster than PL/SQL
David Roth Received on Fri Jun 02 1995 - 00:00:00 CEST