Oops...no, I meant to say "keep" the one with the latest insert
timestamp and delete all of the others. Everyone seems to have caught
the error; deleting the latest would allow duplicates to remain if
there were more than 2 duplicate rows!
- Rachel Carmichael <wisernet100_at_yahoo.com> wrote:
> t2.timestamp > t1.timestamp?
>
> he wants to delete the LATEST insert timestamp, right Paul?
>
> --- Regina Harter <rharter_at_emc-inc.com> 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!?
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> > >http://personals.yahoo.com
> > >--
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> > >--
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> > >
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> __________________________________________________
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> Author: Rachel Carmichael
> INET: wisernet100_at_yahoo.com
>
> Fat City Network Services -- (858) 538-5051 FAX: (858) 538-5051
> San Diego, California -- Public Internet access / Mailing
> Lists
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> 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: Paul Baumgartel
INET: treegarden_at_yahoo.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
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also send the HELP command for other information (like subscribing).
Received on Fri Nov 02 2001 - 08:51:18 CST
