How to find duplicate record in Oracle

It´s easy, you just query twice your table when rowid are lower and all columns are the same. e.g.

select t1.rowid from table1 tb1,table1 tb2
where t1.rowid<t2.rowid
and
t1.col1=t2.col1 and
t1.col2=t2.col2 and
t1.col3=t2.col2 and
t1.col4=t2.col2 and
t1.col5=t2.col2 and …….