List the customer's ID and last name of the customer that purchased a product with a quantity greater than 90% of the average quantity of all listed products.
quantity greater than 90% of the average quantity = Quantity > MULTIPLY(AVG(Quantity), 0.9);
SELECT T2.CustomerID, T2.LastName FROM Sales AS T1 INNER JOIN Customers AS T2 ON T1.CustomerID = T2.CustomerID WHERE T1.Quantity > ( SELECT AVG(Quantity) FROM Sales ) * 0.9