Calculate the total production for each product which were supplied from Japan
from Japan refers to Country = 'Japan'; total production refers to ADD(UnitsInstock, UnitsOnOrder)
SELECT SUM(T1.UnitsInStock + T1.UnitsOnOrder) FROM Products AS T1 INNER JOIN Suppliers AS T2 ON T1.SupplierID = T2.SupplierID WHERE T2.Country = 'Japan'