SQL Query To Use RowNum

select * from ( select r.id, r.subject, r.retry_at, from demo r where retry_at < to_timestamp(to_char(systimestamp,'YYYYMMDDHH24MISSFF'), 'YYYYMMDDHH24MISSFF') order by r.retry_at desc) where rownum <= 2;

Note That We Used Outer Query for rownum