SELECT
  i_product_name,
  i_brand,
  i_class,
  i_category,
  avg(inv_quantity_on_hand) qoh
FROM inventory, date_dim, item, warehouse
WHERE inv_date_sk = d_date_sk
  AND inv_item_sk = i_item_sk
  AND inv_warehouse_sk = w_warehouse_sk
  AND d_month_seq BETWEEN 1200 AND 1200 + 11
GROUP BY ROLLUP (i_product_name, i_brand, i_class, i_category)
ORDER BY qoh, i_product_name, i_brand, i_class, i_category
LIMIT 100