TPC-DS Q39A

WITH inv AS (
  SELECT
    w_warehouse_name AS w_warehouse_name,
    w_warehouse_sk AS w_warehouse_sk,
    i_item_sk AS i_item_sk,
    d_moy AS d_moy,
    stdev AS stdev,
    mean AS mean,
    CASE mean WHEN 0 THEN NULL ELSE stdev / mean END AS cov
  FROM (
    SELECT
      w_warehouse_name AS w_warehouse_name,
      w_warehouse_sk AS w_warehouse_sk,
      i_item_sk AS i_item_sk,
      d_moy AS d_moy,
      STDEV(inv_quantity_on_hand) AS stdev,
      AVG(inv_quantity_on_hand) AS mean
    FROM inventory, item, warehouse, date_dim
    WHERE
      inv_item_sk = i_item_sk
      AND inv_warehouse_sk = w_warehouse_sk
      AND inv_date_sk = d_date_sk
      AND d_year = 2001
    GROUP BY
      w_warehouse_name,
      w_warehouse_sk,
      i_item_sk,
      d_moy
  ) AS foo
  WHERE
    CASE mean WHEN 0 THEN 0 ELSE stdev / mean END > 1
)
SELECT
  inv1.w_warehouse_sk,
  inv1.i_item_sk,
  inv1.d_moy,
  inv1.mean,
  inv1.cov,
  inv2.w_warehouse_sk,
  inv2.i_item_sk,
  inv2.d_moy,
  inv2.mean,
  inv2.cov
FROM inv AS inv1, inv AS inv2
WHERE
  inv1.i_item_sk = inv2.i_item_sk
  AND inv1.w_warehouse_sk = inv2.w_warehouse_sk
  AND inv1.d_moy = 2
  AND inv2.d_moy = 2 + 1
ORDER BY
  inv1.w_warehouse_sk,
  inv1.i_item_sk,
  inv1.d_moy,
  inv1.mean,
  inv1.cov,
  inv2.d_moy,
  inv2.mean,
  inv2.cov;