SQL select, sum and group simple problem

See more:

SQL-Server

SELECT     Product.Name, SUM(Product.Quantity) AS Balance, SUM(Income.IncomeQuantity) AS income, SUM(ProductLog.Quantity) as sold
    FROM         Income INNER JOIN
                          Product ON Income.ProductID = Product.ID INNER JOIN
                          ProductLog ON Product.ID = ProductLog.ProductID GROUP BY Name

This query does not works correctly. In product table and income is three rows and this query returns only two because productLog table contains data only two products. how i can select if productLog or income does not contains current product id return 0

see screenshot http://imageshack.us/photo/my-images/12/capturezfs.png/[^]