Oracle Analytic Function

–USE ANALYTIC FUNCTION TO DELETE ALL BUT ORIGINAL
delete from <TABLE_NAME>
where (key1, ins_timestamp) in
(select key1, ins_timestamp from
(
select key1, ins_timestamp, upd_timestamp
, row_number() over (partition by key1 order by ins_timestamp) as rownumber
from <TABLE_NAME>
) t1
where rownumber > 1);