SELECT
channel,
col_name,
d_year,
d_qoy,
i_category,
COUNT(*) sales_cnt,
SUM(ext_sales_price) sales_amt
FROM (
SELECT
'store' AS channel,
ss_store_sk col_name,
d_year,
d_qoy,
i_category,
ss_ext_sales_price ext_sales_price
FROM store_sales, item, date_dim
WHERE ss_store_sk IS NULL
AND ss_sold_date_sk = d_date_sk
AND ss_item_sk = i_item_sk
UNION ALL
SELECT
'web' AS channel,
ws_ship_customer_sk col_name,
d_year,
d_qoy,
i_category,
ws_ext_sales_price ext_sales_price
FROM web_sales, item, date_dim
WHERE ws_ship_customer_sk IS NULL
AND ws_sold_date_sk = d_date_sk
AND ws_item_sk = i_item_sk
UNION ALL
SELECT
'catalog' AS channel,
cs_ship_addr_sk col_name,
d_year,
d_qoy,
i_category,
cs_ext_sales_price ext_sales_price
FROM catalog_sales, item, date_dim
WHERE cs_ship_addr_sk IS NULL
AND cs_sold_date_sk = d_date_sk
AND cs_item_sk = i_item_sk) foo
GROUP BY channel, col_name, d_year, d_qoy, i_category
ORDER BY channel, col_name, d_year, d_qoy, i_category
LIMIT 100
