Need to retrieve the most recent record per deposit number

Question

Can someone please show me a way to solve my problem or at least point me in the right direction.
I have a simple bibliography table called mdd_biblio that has 3 fields:
bib_mdd_no this is a deposit number
bib_upd_by person who updated the record
bib_upd_date date the record was updated (timestamp)
A deposit might have more than one bibliographic entry with either the same date or a newer date and, the deposit might have one or more person updating the bibliography
The table has 4974 records but only 1867 are unique deposit numbers
All I want to do is select a single record that indicates when the deposit was last edited and and who did the editing (as indicated by the *). I don't care which record it is as long as it is the most recent date.
The following query retrieves 1944 records (67 duplicates) and has eliminated 3000 duplicates but hasn't eliminated them all. Why?
select unique(bib_mdd_no), bib_upd_by, bib_upd_date from mdd_biblio
order by bib_mdd_no
M64C/16-001 MDD 13-SEP-07 *
M64C/16-001 MDD 13-SEP-07
M64C/16-002 DPROUXE 30-NOV-07 *
M64C/16-002 MDD 13-SEP-07
M64C/16-002 MDD 13-SEP-07
M64C/16-003 DPROUXE 29-NOV-07 *
M64C/16-003 MDD 13-SEP-07
M64C/16-003 MDD 13-SEP-07
M64C/16-004 MDD 13-SEP-07 *
M64C/16-004 MDD 13-SEP-07
M64C/16-005 MDD 13-SEP-07 *
M64C/16-005 MDD 13-SEP-07
M64C/16-006 DPROUXE 03-DEC-07 *
M64C/16-006 MDD 13-SEP-07
M64C/16-007 MDD 02-OCT-07 *
M64C/16-008 MDD 02-OCT-07 *
M64C/16-009 MDD 02-OCT-07 *
M64C/16-010 MDD 02-OCT-07 *
I don't understand why of these duplicates still show up here since 3000 have been eliminated..
To Reiterate: What I really need is a simple query to retrieve the most recently edited record for each deposit number regardless of the updater's name. I need this in order to build a summary table from this and 15 other tables.
Thanks for any help you can give
Glenn

Answer 1

Usually it is done somehow like this
select bib_mdd_no,
       bib_upd_by,
       bib_upd_date
  from (select bib_mdd_no,
               bib_upd_by,
               bib_upd_date,
               row_number() over (partition by bib_mdd_no order by bib_upd_date desc) r
          from mdd_biblio
where r = 1
order by bib_mdd_noRegards
Etbin