-- Q11: Important Stock Identification
-- Operators: 3-table Join -> Aggregate -> HAVING (scalar subquery)
SELECT
    ps_partkey,
    SUM(ps_supplycost * ps_availqty) AS value
FROM partsupp, supplier, nation
WHERE ps_suppkey = s_suppkey
  AND s_nationkey = n_nationkey
  AND n_name = 'GERMANY'
GROUP BY ps_partkey
HAVING SUM(ps_supplycost * ps_availqty) > (
    SELECT SUM(ps_supplycost * ps_availqty) * 0.0001
    FROM partsupp, supplier, nation
    WHERE ps_suppkey = s_suppkey
      AND s_nationkey = n_nationkey
      AND n_name = 'GERMANY'
)