Question

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 I don’t pass any value it should be null and if I pass some value it should take it. I don’t want to go and change all the stored procedures to do so.

Example code

dbo.CalculateAverageForUser(userid int)

Can I use dbo.CalculateAverageForUser(userid int, type NVARCHAR(10) = NULL)

Answer 1

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