compute 4! using a recursive with clause

ch7_1.sql

WITH RSFC(ITERATION,RUNNING_FACTORIAL) AS
  ( SELECT NUM AS ITERATION, 1 AS RUNNING_FACTORIAL FROM NUMBERS WHERE NUM =1
  UNION ALL
  SELECT R.ITERATION +1,
    R.RUNNING_FACTORIAL * B.NUM
  FROM RSFC R
  INNER JOIN NUMBERS B
  ON (R.ITERATION+1) = B.NUM
  )
SELECT iteration,running_factorial FROM rsfc