From john.hallas@mail.com Thu, 01 Mar 2001 03:08:28 -0800 From: "John Hallas" Date: Thu, 01 Mar 2001 03:08:28 -0800 Subject: RE: Help - Tuning SQL Message-ID: MIME-Version: 1.0 Content-Type: text/plain 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: maa25681@GlaxoWellcome.com 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: ListGuru@fatcity.com (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: john.hallas@mail.com 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: ListGuru@fatcity.com (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).