This following code gives example, how to declare null able parameter inside a store procedure:
CREATE PROCEDURE [dbo].[usp_Customer]
@CustomerID int,
@CustomerName nvarchar(50) = NULL,
AS
BEGIN
ENDThis example of declaring null able parameter inside store procedure.
CREATE PROCEDURE [dbo].[usp_Customer]
@CustomerID int,
@CustomerName nvarchar(50) = NULL,
AS
BEGIN
END