Listing 1

SQL 7

Add It Up

SELECT CustomerID, 'OrderTotal' = 
   SUM(UnitPrice * Quantity),
   'TotalFreight' = SUM(Freight)
FROM ORDERS
INNER JOIN [Order Details]
ON Orders.OrderID = [Order Details].OrderID
GROUP BY CustomerID
ORDER BY CustomerID

CustomerID    OrderTotal   TotalFreight
----------  -----------  -----------
ALFKI          4596.2000   419.6000
ANATR          1402.9500   306.5900
ANTON          7515.3500   667.2900
AROUT          13806.5000   1447.1400
BERGS          26968.1500   4835.1800

Listing 1 You can use the SUM function in a GROUP BY clause to get totals for each customer. Like all aggregate functions, SUM isn't powerful in and of itself, but you can combine it with other functions to powerful effect.