text: -- Q14 (tpch2.6.1)
  
  SELECT
      100.00 * SUM(CASE WHEN P_TYPE LIKE 'PROMO%'
                     THEN L_EXTENDEDPRICE * (1 - L_DISCOUNT)
                     ELSE 0
                  END) / SUM(L_EXTENDEDPRICE * (1 - L_DISCOUNT))
                  AS PROMO_REVENUE
  FROM TPCH.LINEITEM, TPCH.PART
  WHERE L_PARTKEY = P_PARTKEY
      AND L_SHIPDATE >= DATE'1995-09-01'
      AND L_SHIPDATE < DATE'1995-10-01';
  