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-- 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,
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-- limitations under the License.

with inv as
(select w_warehouse_name,w_warehouse_sk,i_item_sk,d_moy
       ,stdev,mean, case mean when 0 then null else stdev/mean end cov
 from(select w_warehouse_name,w_warehouse_sk,i_item_sk,d_moy
            ,stddev_samp(inv_quantity_on_hand) stdev,avg(inv_quantity_on_hand) mean
      from inventory
          ,item
          ,warehouse
          ,date_dim
      where inv_item_sk = i_item_sk
        and inv_warehouse_sk = w_warehouse_sk
        and inv_date_sk = d_date_sk
        and d_year =1999
      group by w_warehouse_name,w_warehouse_sk,i_item_sk,d_moy) foo
 where case mean when 0 then 0 else stdev/mean end > 1)
select inv1.w_warehouse_sk,inv1.i_item_sk,inv1.d_moy,inv1.mean, inv1.cov
        ,inv2.w_warehouse_sk,inv2.i_item_sk,inv2.d_moy,inv2.mean, inv2.cov
from inv inv1,inv inv2
where inv1.i_item_sk = inv2.i_item_sk
  and inv1.w_warehouse_sk =  inv2.w_warehouse_sk
  and inv1.d_moy=4
  and inv2.d_moy=4+1
  and inv1.cov > 1.5
order by inv1.w_warehouse_sk,inv1.i_item_sk,inv1.d_moy,inv1.mean,inv1.cov
        ,inv2.d_moy,inv2.mean, inv2.cov