Deleting duplicated records by date

Question

Hi,
what could I do to delete duplicated records from test1 table
the test1 table have the next columns that I describe below:
code
operator
phone
init_date
end_date The records are duplicated by code, operator, phone, init_date
and I need to delete the records with min(end_date)
thanks in advanced...

Answer 1

/* Formatted on 1/12/2012 7:28:44 AM (QP5 v5.149.1003.31008) */
CREATE TABLE data
AS
   (SELECT 'A' code,
           'Bob' operator,
           '111-2222' phone,
           ADD_MONTHS (SYSDATE, -1) init_date,
           SYSDATE end_date
      FROM DUAL
    UNION ALL
    SELECT 'A',
           'Bob',
           '111-2222',
           ADD_MONTHS (SYSDATE, -1) init_date,
           SYSDATE + 1 end_date
      FROM DUAL);
DELETE FROM data
      WHERE (code, operator, phone, init_date, end_date) IN
               (SELECT code,
                       operator,
                       phone,
                       init_date,
                       end_date
                  FROM (SELECT data.*,
                               COUNT (
                               OVER (
                                  PARTITION BY code,
                                               operator,
                                               phone,
                                               init_date)
                                  cnt,
                               ROW_NUMBER ()
                               OVER (
                                  PARTITION BY code,
                                               operator,
                                               phone,
                                               init_date
                                  ORDER BY end_date)
                                  rn
                          FROM data)
                 WHERE cnt > 1 AND rn = 1);