Question

I have a table structure similar to this:

    id | order1_id | order1_type | order1_amount | order2_id | order2_type | order2_amount
------------------------------------------------------------------------------------------
    1        1           3             4                 1         4              5
    2        2           1             1                 1         3              2
    3        1           4             4                 2         2              1

I want to get the data like this:

order_id | order_type | order_amount

1          3            6
1          4            9
2          1            1
2          2            1

I want to group by type, and sum the order amounts. How can I do that ?

Thanks,

Answer 1

I’m going to use a union in a subquery to line the columns up, then group and sum on that.

Assuming you’re stuck with this less-than-ideal table structure, you may want to create a view that represents the subquery below, then run the group by/sum against that view. I’m guessing such a view might be useful in more places than just this one query.

select t.order_id, t.order_type, sum(t.order_amount)
from (select order1_id as order_id, order1_type as order_type, order1_amount as order_amount
      from orders
      union all
      select order2_id as order_id, order2_type as order_type, order2_amount as order_amount
      from orders  
      union all        
      select order3_id as order_id, order3_type as order_type, order3_amount as order_amount
      from orders 
      union all         
      select order4_id as order_id, order4_type as order_type, order4_amount as order_amount
      from orders    
      union all      
      select order5_id as order_id, order5_type as order_type, order5_amount as order_amount
      from orders) t
group by t.order_id, t.order_type