MySQL Adding & Multiple Columns On Select

Question

My database looks as follows

Table Name: Order Details

id       oid      pid   pquantity  pprice
--------------------------------------
  1       1       5        2       10
  2       1       6        3       5
  3       1       7        1       20
  5       2       8        1       5
  6       2       9        1       5
  7       3       5        5       10

Table Name: Orders

id       odiscount oshipping
----------------------------
  1       5       5        
  2       0       5        
  3       0       5  

I want to get the invoice value for each order. (pquantity*pprice)-odiscount+oshipping. The tricky part is that each order can have multiple entries in order details. So I am unable to figure out how to take care of that. The end result should be

oid   total
1     55
2     15
3     55

I tried this using the following SQL but I am unable to figure out how to take multiple rows in order details into account.

SELECT SUM((orderdetails.pprice*orderdetails.pquantity) - orders.odiscount + orders.oshipping) FROM orders LEFT JOIN orderdetails ON orderdetails.oid = orders.id GROUP BY orders.id

Answer 1

I believe you can do this without even using a subquery:

SELECT SUM(od.pquantity*od.pprice) + AVG(o.oshipping - o.odiscount)
FROM Orders o
INNER JOIN OrderDetails od
    ON o.id = od.oid
GROUP BY o.id

Demo here:

SQLFiddle