TPC-DS Q51

WITH web_v1 AS (
  SELECT
    ws_item_sk AS item_sk,
    d_date AS d_date,
    SUM(SUM(ws_sales_price)) OVER (
      PARTITION BY ws_item_sk
      ORDER BY d_date
      rows BETWEEN UNBOUNDED preceding AND CURRENT ROW
    ) AS cume_sales
  FROM web_sales, date_dim
  WHERE
    ws_sold_date_sk = d_date_sk
    AND d_month_seq BETWEEN 1190 AND 1190 + 11
    AND NOT ws_item_sk IS NULL
  GROUP BY
    ws_item_sk,
    d_date
), store_v1 AS (
  SELECT
    ss_item_sk AS item_sk,
    d_date AS d_date,
    SUM(SUM(ss_sales_price)) OVER (
      PARTITION BY ss_item_sk
      ORDER BY d_date
      rows BETWEEN UNBOUNDED preceding AND CURRENT ROW
    ) AS cume_sales
  FROM store_sales, date_dim
  WHERE
    ss_sold_date_sk = d_date_sk
    AND d_month_seq BETWEEN 1190 AND 1190 + 11
    AND NOT ss_item_sk IS NULL
  GROUP BY
    ss_item_sk,
    d_date
)
SELECT
TOP 100
  *
FROM (
  SELECT
    item_sk AS item_sk,
    d_date AS d_date,
    web_sales AS web_sales,
    store_sales AS store_sales,
    MAX(web_sales) OVER (
      PARTITION BY item_sk
      ORDER BY d_date
      rows BETWEEN UNBOUNDED preceding AND CURRENT ROW
    ) AS web_cumulative,
    MAX(store_sales) OVER (
      PARTITION BY item_sk
      ORDER BY d_date
      rows BETWEEN UNBOUNDED preceding AND CURRENT ROW
    ) AS store_cumulative
  FROM (
    SELECT
      CASE WHEN NOT web.item_sk IS NULL THEN web.item_sk ELSE store.item_sk END AS item_sk,
      CASE WHEN NOT web.d_date IS NULL THEN web.d_date ELSE store.d_date END AS d_date,
      web.cume_sales AS web_sales,
      store.cume_sales AS store_sales
    FROM web_v1 AS web
    FULL OUTER JOIN store_v1 AS store
      ON (
        web.item_sk = store.item_sk AND web.d_date = store.d_date
      )
  ) AS x
) AS y
WHERE
  web_cumulative > store_cumulative
ORDER BY
  item_sk,
  d_date;