random

WITH g AS
  (SELECT NULL FROM sys.obj$ WHERE rownum<=5000)
SELECT COUNT(*)
FROM
  (SELECT ora_hash(rownum, 50) x
   FROM
     g g1, g g2
   WHERE
     rownum <= 5e6
  )
WHERE x>=0;


            COUNT(*)
--------------------
             5000000
Elapsed: 00:00:01.77