How to delete duplicates in oracle 10g ( strange behaviour)

Question

Recently we migrated from oracel 8i to oralce 10g and we face this problem.
When we try to delete duplicates using rowid ( analytical functions row_number()/
or normal delete ) and commit the same , still we find some duplicates to be existing because of which we are not able to enable costriants and resulting in process failure.
When we run the same delete statement next time it removes more duplicates than the required or sometimes required duplicates resulting in abnormal behaviour.
I don not understand this strange behaviour after upgrading to oracle 10g.
It'd be great if some one who has idea on this can throw light on the same.
thanks

Answer 1

Gasparotto,
Thanks a lot for letting me know a new procedure to delete duplicates sing lead function.
I've tried this code on a temp table and it worked, let me use the same query on the prodn side and test the same.
Procedure for deletion of duplicates using lead analytical function.
create table temp ( col1 number(2) , col2 number(2) , col3 number(2));
insert into temp values ( 1,2,10);
insert into temp values ( 1,2,20);
insert into temp values ( 1,2,30);
insert into temp values ( 3,2,10);
insert into temp values ( 3,4,12);
insert into temp values ( 3,4,45);
commit;
COL1 COL2 COL3
1 2 10
1 2 20
1 2 30
3 2 10
3 4 12
3 4 45
select col1,col2 , col3, LEAD(rowid) OVER (PARTITION BY col1,col2 order by null) from temp;
COL1 COL2 COL3 LEAD(ROWID)OVER(PA
1 2 10 AAAVBjAApAAAFyGAAB
1 2 20 AAAVBjAApAAAFyGAAC
1 2 30
3 2 10
3 4 12 AAAVBjAApAAAFyGAAF
3 4 45
6 rows selected.
select rowid , temp.* from temp ;
ROWID COL1 COL2 COL3
AAAVBjAApAAAFyGAAA 1 2 10
AAAVBjAApAAAFyGAAB 1 2 20
AAAVBjAApAAAFyGAAC 1 2 30
AAAVBjAApAAAFyGAAD 3 2 10
AAAVBjAApAAAFyGAAE 3 4 12
AAAVBjAApAAAFyGAAF 3 4 45
SQL> DELETE temp
WHERE rowid IN
( SELECT LEAD(rowid) OVER (PARTITION BY col1, col2 ORDER BY null)
FROM temp ); 2 3 4
3 rows deleted.
SQL> select rowid , temp.* from temp ;
ROWID COL1 COL2 COL3
AAAVBjAApAAAFyGAAA 1 2 10
AAAVBjAApAAAFyGAAD 3 2 10
AAAVBjAApAAAFyGAAE 3 4 12
Thanks for the reply