q51.sql

WITH web_v1 AS (
  SELECT
    ws_item_sk item_sk,
    d_date,
    sum(sum(ws_sales_price))
    OVER (PARTITION BY ws_item_sk
      ORDER BY d_date
      ROWS BETWEEN UNBOUNDED PRECEDING AND CURRENT ROW) cume_sales
  FROM web_sales, date_dim
  WHERE ws_sold_date_sk = d_date_sk
    AND d_month_seq BETWEEN 1200 AND 1200 + 11
    AND ws_item_sk IS NOT NULL
  GROUP BY ws_item_sk, d_date),
    store_v1 AS (
    SELECT
      ss_item_sk item_sk,
      d_date,
      sum(sum(ss_sales_price))
      OVER (PARTITION BY ss_item_sk
        ORDER BY d_date
        ROWS BETWEEN UNBOUNDED PRECEDING AND CURRENT ROW) cume_sales
    FROM store_sales, date_dim
    WHERE ss_sold_date_sk = d_date_sk
      AND d_month_seq BETWEEN 1200 AND 1200 + 11
      AND ss_item_sk IS NOT NULL
    GROUP BY ss_item_sk, d_date)
SELECT *
FROM (SELECT
  item_sk,
  d_date,
  web_sales,
  store_sales,
  max(web_sales)
  OVER (PARTITION BY item_sk
    ORDER BY d_date
    ROWS BETWEEN UNBOUNDED PRECEDING AND CURRENT ROW) web_cumulative,
  max(store_sales)
  OVER (PARTITION BY item_sk
    ORDER BY d_date
    ROWS BETWEEN UNBOUNDED PRECEDING AND CURRENT ROW) store_cumulative
FROM (SELECT
  CASE WHEN web.item_sk IS NOT NULL
    THEN web.item_sk
  ELSE store.item_sk END item_sk,
  CASE WHEN web.d_date IS NOT NULL
    THEN web.d_date
  ELSE store.d_date END d_date,
  web.cume_sales web_sales,
  store.cume_sales store_sales
FROM web_v1 web FULL OUTER JOIN store_v1 store ON (web.item_sk = store.item_sk
  AND web.d_date = store.d_date)
     ) x) y
WHERE web_cumulative > store_cumulative
ORDER BY item_sk, d_date
LIMIT 100;