if you handle for nulls with an 'nvl' then 'not exists' appears to return the same answer as not in.
or am I wrong? ----- Original Message ----- To: "Multiple recipients of list ORACLE-L" <[EMAIL PROTECTED]> Sent: Sunday, September 21, 2003 3:24 PM > First off, the three are not equivalent, not substitutes for each other. > Well not in and minus would be, but they are different from not exists. > "not in"/"minus" and "not exists" can return different results. See > <http://asktom.oracle.com/pls/ask/f?p=4950:8:::::F4950_P8_DISPLAYID:44202973 7684>http://asktom.oracle.com/pls/ask/f?p=4950:8:::::F4950_P8_DISPLAYID:4420 29737684 > > > for examples and explanation. > > I have not done any performance comparisons but I personally routinely use > minus and I am quite happy with it, especially across a db link. > > At 09:59 AM 9/21/2003 -0800, you wrote: > >Do any of you have any cases when minus is superior in performance? Ive > >found 'not in' with a hash_aj to be the best option if the sub-query is > >significantly less 'costly' then the outer query. I dont mean cost in > >terms of the Explain Plan, I mean the work Oracle has to do to find a > >result set. It also depends on a proper hash_area_size > > > >I find 'where not exists' to be best if the subquery is relatively close > >in cost to the outer query. Yes I know you cant make broad > >generalizations, but there has to be some 'narrow' generalizations you can > >make. Such as certain cases, etc... > > > >what have you seen? There seems to be very little work in this area in the > >literature. > > > >Does 'where not exist' need more or less sort_area_size space than minus? > > Wolfgang Breitling > Oracle7, 8, 8i, 9i OCP DBA > Centrex Consulting Corporation > http://www.centrexcc.com > > -- > Please see the official ORACLE-L FAQ: http://www.orafaq.net > -- > Author: Wolfgang Breitling > INET: [EMAIL PROTECTED] > > Fat City Network Services -- 858-538-5051 http://www.fatcity.com > San Diego, California -- Mailing list and web hosting services > --------------------------------------------------------------------- > 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.net -- Author: Ryan INET: [EMAIL PROTECTED] Fat City Network Services -- 858-538-5051 http://www.fatcity.com San Diego, California -- Mailing list and web hosting services --------------------------------------------------------------------- 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).
