text: --q93.sql--
  
   select ss_customer_sk, sum(act_sales) sumsales
   from (select
           ss_item_sk, ss_ticket_number, ss_customer_sk,
           case when sr_return_quantity is not null then (ss_quantity-sr_return_quantity)*ss_sales_price
                                                    else (ss_quantity*ss_sales_price) end act_sales
         from store_sales
         left outer join store_returns
         on (sr_item_sk = ss_item_sk and sr_ticket_number = ss_ticket_number),
         reason
         where sr_reason_sk = r_reason_sk and r_reason_desc = 'reason 28') t
   group by ss_customer_sk
   order by sumsales, ss_customer_sk
   limit 100
              
  