Delete duplicate rows in a table

To delete the duplicate rows from a table.

Method 1 :

create table newtable as (select distinct * from oldtable);

drop table oldtable;

rename newtable to oldtable;

Method 2:

DELETE FROM mytable t1
      WHERE ROWID < (SELECT MAX (ROWID)
                       FROM mytable t2
                      WHERE t1.col1 = t2.col1 AND t1.col2 = t2.col2)