I thinks it more that people often use it where it is not required. For example, they'll code (in PL/SQL)
select some_expression into variable from dual instead of variable := some_expression; The other side of the equation is excessive use of SYSDATE or USER in PL/SQL, because x := sysdate; is converted to 'select sysdate into x from dual' hth connor --- Thomas Jeff <[EMAIL PROTECTED]> wrote: > On page 92 of Oracle Performance Tuning 101, there's > a recommendation > to avoid the use of SELECT X FROM DUAL, claiming > that it can '..use up > system > performance in a hurry', but does not go on to > elaborate as to exactly > *why*. > > Could someone shed a bit more light on this? > Thanks. > > -------------------------------------------- > Jeffery D Thomas > DBA > Thomson Information Services > Thomson multimedia Inc. > > Email: [EMAIL PROTECTED] > DBA Quickplace: http://gkmqp.tce.com/tis_dba > -------------------------------------------- > > > ===== Connor McDonald http://www.oracledba.co.uk (mirrored at http://www.oradba.freeserve.co.uk) "Some days you're the pigeon, some days you're the statue" __________________________________________________ Do You Yahoo!? Everything you'll ever need on one web page from News and Sport to Email and Music Charts http://uk.my.yahoo.com -- Please see the official ORACLE-L FAQ: http://www.orafaq.com -- Author: =?iso-8859-1?q?Connor=20McDonald?= 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).
