t2.timestamp > t1.timestamp? he wants to delete the LATEST insert timestamp, right Paul?
--- Regina Harter <[EMAIL PROTECTED]> wrote: > Try this: > > Delete from my_table t1 > where a = 2 and exists > (select 'X' from my_table t2 > where t2.a = t1.a > and t2.b = t1.b > and t2.c = t1.b > and t2.d = t1.d > and t2.timestamp < t1.timestamp) > > At 12:55 PM 11/1/01 -0800, you wrote: > >Given a business rule that says a combination of three columns must > be > >unique if and only if a fourth column equals a certain value, and if > >the table in question contains rows that violate this requirement, > I'm > >trying to write a single SQL statement that will remove the > duplicates. > > Of each set of duplicate rows, I'll delete the one with the latest > >insert timestamp. > > > >Let's call the columns > > > >a b c d timestamp > > > >The combination of b, c, and d must be unique if a = 2. > > > >I can get the duplicate row values along with the latest timestamp > via > > > >select max(tstamp), a, b, c from > >my_table group by a, b, c having count(*) > 1 > > > >But I can't figure out how to use that in a delete statement. > > > >Suggestions greatly appreciated! > > > > > >Paul Baumgartel > > > > > >__________________________________________________ > >Do You Yahoo!? > >Make a great connection at Yahoo! Personals. > >http://personals.yahoo.com > >-- > >Please see the official ORACLE-L FAQ: http://www.orafaq.com > >-- > >Author: Paul Baumgartel > > 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: Regina Harter > 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). __________________________________________________ Do You Yahoo!? Find a job, post your resume. http://careers.yahoo.com -- Please see the official ORACLE-L FAQ: http://www.orafaq.com -- Author: Rachel Carmichael 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).
