select 'web' as channel
     , web.item
     , web.return_ratio
     , web.return_rank
     , web.currency_rank
from (select item
           , return_ratio
           , currency_ratio
           , rank() over (order by return_ratio) as return_rank
 	,rank() over (order by currency_ratio) as currency_rank
      from (select ws.ws_item_sk                                              as item
                 , (cast(sum(coalesce(wr.wr_return_quantity, 0)) as decimal(15, 4)) /
                    cast(sum(coalesce(ws.ws_quantity, 0)) as decimal(15, 4))) as return_ratio
                 , (cast(sum(coalesce(wr.wr_return_amt, 0)) as decimal(15, 4)) /
                    cast(sum(coalesce(ws.ws_net_paid, 0)) as decimal(15, 4))) as currency_ratio
            from web_sales ws
                     left outer join web_returns wr
                                     on (ws.ws_order_number = wr.wr_order_number and
                                         ws.ws_item_sk = wr.wr_item_sk)
               , date_dim
            where wr.wr_return_amt > 10000
              and ws.ws_net_profit > 1
              and ws.ws_net_paid > 0
              and ws.ws_quantity > 0
              and ws_sold_date_sk = d_date_sk
              and d_year = 2001
              and d_moy = 12
            group by ws.ws_item_sk) in_web) web
where (
                  web.return_rank <= 10
              or
                  web.currency_rank <= 10
          )
union
select 'catalog' as channel
     , catalog.item
     , catalog.return_ratio
     , catalog.return_rank
     , catalog.currency_rank
from (select item
           , return_ratio
           , currency_ratio
           , rank() over (order by return_ratio) as return_rank
 	,rank() over (order by currency_ratio) as currency_rank
      from (select cs.cs_item_sk                                              as item
                 , (cast(sum(coalesce(cr.cr_return_quantity, 0)) as decimal(15, 4)) /
                    cast(sum(coalesce(cs.cs_quantity, 0)) as decimal(15, 4))) as return_ratio
                 , (cast(sum(coalesce(cr.cr_return_amount, 0)) as decimal(15, 4)) /
                    cast(sum(coalesce(cs.cs_net_paid, 0)) as decimal(15, 4))) as currency_ratio
            from catalog_sales cs
                     left outer join catalog_returns cr
                                     on (cs.cs_order_number = cr.cr_order_number and
                                         cs.cs_item_sk = cr.cr_item_sk)
               , date_dim
            where cr.cr_return_amount > 10000
              and cs.cs_net_profit > 1
              and cs.cs_net_paid > 0
              and cs.cs_quantity > 0
              and cs_sold_date_sk = d_date_sk
              and d_year = 2001
              and d_moy = 12
            group by cs.cs_item_sk) in_cat) catalog
where
    (
    catalog.return_rank <= 10
   or
    catalog.currency_rank <=10
    )
union
select 'store' as channel
     , store.item
     , store.return_ratio
     , store.return_rank
     , store.currency_rank
from (select item
           , return_ratio
           , currency_ratio
           , rank() over (order by return_ratio) as return_rank
 	,rank() over (order by currency_ratio) as currency_rank
      from (select sts.ss_item_sk                                              as item
                 , (cast(sum(coalesce(sr.sr_return_quantity, 0)) as decimal(15, 4)) /
                    cast(sum(coalesce(sts.ss_quantity, 0)) as decimal(15, 4))) as return_ratio
                 , (cast(sum(coalesce(sr.sr_return_amt, 0)) as decimal(15, 4)) /
                    cast(sum(coalesce(sts.ss_net_paid, 0)) as decimal(15, 4))) as currency_ratio
            from store_sales sts
                     left outer join store_returns sr
                                     on (sts.ss_ticket_number = sr.sr_ticket_number and sts.ss_item_sk = sr.sr_item_sk)
               , date_dim
            where sr.sr_return_amt > 10000
              and sts.ss_net_profit > 1
              and sts.ss_net_paid > 0
              and sts.ss_quantity > 0
              and ss_sold_date_sk = d_date_sk
              and d_year = 2001
              and d_moy = 12
            group by sts.ss_item_sk) in_store) store
where (
                  store.return_rank <= 10
              or
                  store.currency_rank <= 10
          )
order by 1, 4, 5 limit 100
