I have a user defined function which is used in many stored procedures which will return me some value. If it possible for me to add a new optional parameter to the same.
If you don't want to go adjusting all of your existing stored procedures that reference the function then I think you would need to create a new function with the code from your existing one
CREATE FUNCTION CalculateAverageForUser2
(
@userid int,
@param2 nvarchar(10) = NULL
)
RETURNS float
AS
/*Code from existing function goes here*/
Then just change the existing function to the following
ALTER FUNCTION CalculateAverageForUser
(
@userid int
)
RETURNS float
AS
BEGIN
RETURN dbo.CalculateAverageForUser2(@userid, DEFAULT)
END