Top 5 Heavy Query ( 10g or above)

--- TOP 5 QUERY BASED ON LAST 60 MINUTES

select *

  from (select s.BUFFER_GETS,

               s.DISK_READS,

               nvl(s.sql_id, 'null') as id,

               Nvl(S.sql_text, 'NULL') AS SQL_ID,

               round(COUNT(*) / 60, 2) DB_TIME,

               ROUND(100 * COUNT(*) / SUM(COUNT(*)) OVER(), 2) AS PCT_LOAD

          FROM V$active_Session_History A, v$SQL S

         WHERE A.SQL_ID = S.SQL_ID

    AND SAMPLE_TIME > SYSDATE - 60 / 24 / 60 --- TIME e.g for 2 hours  120/24/60

           AND SESSION_TYPE <> 'BACKGROUND'

         GROUP BY s.sql_id, s.SQL_text, s.BUFFER_GETS, s.DISK_READS

         ORDER BY COUNT(*) DESC)

 where rownum <= 10; --- HOW MUCH QUERIES