Hive: Sum over a specified group (HiveQL)

Question

I have a table:

key    product_code    cost
1      UK              20
1      US              10
1      EU              5
2      UK              3
2      EU               


        

Answer 1

The analytics function sum gives cumulative sums. For example, if you did:

select key, product_code, cost, sum(cost) over (partition by key) as total_costs from test

then you would get:

key    product_code    cost     total_costs
1      UK              20       20
1      US              10       30
1      EU              5        35
2      UK              3        3
2      EU              6        9

which, it seems, is not what you want.

Instead, you should use the aggregation function sum, combined with a self join to accomplish this:

select test.key, test.product_code, test.cost, agg.total_cost
from (
  select key, sum(cost) as total_cost
  from test
  group by key
) agg
join test
on agg.key = test.key;