text: --  Licensed to the Apache Software Foundation (ASF) under one or more
  --  contributor license agreements. See the NOTICE file distributed with
  --  this work for additional information regarding copyright ownership.
  --  The ASF licenses this file to You under the Apache License, Version 2.0
  --  (the "License"); you may not use this file except in compliance with
  --  the License. You may obtain a copy of the License at
  --
  --    http://www.apache.org/licenses/LICENSE-2.0
  --
  --  Unless required by applicable law or agreed to in writing, software
  --  distributed under the License is distributed on an "AS IS" BASIS,
  --  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  --  See the License for the specific language governing permissions and
  --  limitations under the License.
  
  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
  