SELECT avg(Order_Quantity) FROM Invoices WHERE payment_method_code  =  "MasterCard"
What is the average quantities ordered with payment method code "MasterCard" on invoices?
SELECT avg ( Order_Quantity ) FROM Invoices WHERE payment_method_code = `` MasterCard ''
select avg ( order_quantity ) from invoices where payment_method_code = value
What is the average quantities ordered with payment method code `` MasterCard '' on invoices ?