Question

I have a stored procedure which used for my shopping cart system which returns the total amount and looks like this;

ALTER PROCEDURE [dbo].[ShoppingCartGetTotalAmount]
(@CartID char(36))
AS
SELECT ISNULL(SUM(Product.Price * ShoppingCart.Quantity), 0)
FROM ShoppingCart INNER JOIN Product
ON ShoppingCart.ProductID = Product.ProductID
WHERE ShoppingCart.CartID = @CartID

However, Now I want to do the same thing in Entity Framework. Therefore, I need to know either of the following options;
1) How can I do the above task in Entity FrameWork i-e

SELECT ISNULL(SUM(Product.Price * ShoppingCart.Quantity), 0)
    FROM ShoppingCart INNER JOIN Product
    ON ShoppingCart.ProductID = Product.ProductID
    WHERE ShoppingCart.CartID = @CartID

2) Or What is the Equavilant to the SQL ISNULL() function in C#?
3) Or How can I achieve this -> ISNULL(SUM(Product.Price * ShoppingCart.Quantity), 0)
using any .Net method?

Answer 1

C# has the null coalesce operator – ??.

The ?? operator is called the null-coalescing operator and is used to define a default value for nullable value types or reference types. It returns the left-hand operand if the operand is not null; otherwise it returns the right operand.

EF understands this operator and translates it correctly.