Regarding the first point the easiest way to check is to run explain plan
fro the 2 statements and compare the results
On the second point the != issue
Guy Harrisons's excellent book Oracle SQL - High Performance Tuning states
"Oracle will not employ an index if the NOT EQUALS operator is employed."
Using > and < will use an index (other conditions permitting)
HTH
John
-----Original Message-----
Michael A
Sent: 28 February 2001 19:51
To: Multiple recipients of list ORACLE-L
I've got some simple questions on tuning SQL. Please reply with references,
I'm not looking for guesses.
* If you have a SELECT statement with a WHERE clause and 2 AND
clauses, which one is processed first, the WHERE clause, the first AND
clause, or the second AND clause?
* Is there any performance loss in using "<>" over "!="?
Michael Armstead
Database Administrator, OCP-Certified
Corporate & Finance Information Systems
Glaxo SmithKline
--
Please see the official ORACLE-L FAQ: http://www.orafaq.com
--
Author: Armstead, Michael A
INET: [EMAIL PROTECTED]
Fat City Network Services -- (858) 538-5051 FAX: (858) 538-5051
San Diego, California -- Public Internet access / Mailing Lists
--------------------------------------------------------------------
To REMOVE yourself from this mailing list, send an E-Mail message
to: [EMAIL PROTECTED] (note EXACT spelling of 'ListGuru') and in
the message BODY, include a line containing: UNSUB ORACLE-L
(or the name of mailing list you want to be removed from). You may
also send the HELP command for other information (like subscribing).
--
Please see the official ORACLE-L FAQ: http://www.orafaq.com
--
Author: John Hallas
INET: [EMAIL PROTECTED]
Fat City Network Services -- (858) 538-5051 FAX: (858) 538-5051
San Diego, California -- Public Internet access / Mailing Lists
--------------------------------------------------------------------
To REMOVE yourself from this mailing list, send an E-Mail message
to: [EMAIL PROTECTED] (note EXACT spelling of 'ListGuru') and in
the message BODY, include a line containing: UNSUB ORACLE-L
(or the name of mailing list you want to be removed from). You may
also send the HELP command for other information (like subscribing).
