Need a query for duplicate records deletion

Question

here is one scenario...
23130 ----> 'A'
23130 ----> 'X'
23130 ----> 'c'
These are duplicate records.. when we remove duplicates, the record must get 'c', if it contains A,C,X. If it contains A and X, then the record must get 'X'. That means the priority goes like this C-->X-->A. for this i need query.. this is one scenario. It would be great if u reply me asap.

Answer 1

Hello
It's great that you gave examples of your data, but it is quite helpful to supply create table and insert statements too along with a clear example of expected results. Anyway, I think this does what you are looking for.
CREATE TABLE dt_dup (ID NUMBER, flag VARCHAR2(1))
INSERT INTO dt_dup VALUES(23130, 'A');
insert into dt_dup values(23130, 'X');
insert into dt_dup values(23130, 'C');
INSERT INTO dt_dup VALUES(23131, 'A');
INSERT INTO dt_dup VALUES(23131, 'X');
DELETE
FROM
  dt_dup
WHERE
  ROWID IN (  SELECT
                rid
              FROM
                (   SELECT
                      rowid rid,
                      ROW_NUMBER() OVER (PARTITION BY ID ORDER BY CASE
                                                                    WHEN flag = 'A' THEN
                                                                      3
                                                                    WHEN flag = 'X' THEN
                                                                      2
                                                                    WHEN flag = 'C' THEN
                                                                      1
                                                                  END
                                        ) rn
                    FROM
                      dt_dup
              WHERE
                rn > 1
select * from dt_dup;HTH
David
Edited by: Bravid on Jun 30, 2011 8:12 AM