Consider the SQL query in Figure 1-19.
a. How is Sales to Date calculated?
b. How would the query have to change if Helen Jarvis wanted to see the results for all of the product lines, not just the Home Office product line?

SELECT Product.ProductID, Product.ProductDescription, Product.PRCurrentYearSalesGoal, (OrderQuantity ProductPrice) AS SalesToDate FROM Order.OrderLine, Product.ProductLine WHERE Order.OrderNumber = OrderLine.OrderNumber AND Product.ProductID = OrderedProduct.ProductID AND Product.ProductID = ProductLine.ProductID AND Product.ProductLineName = "Home Office";