Default Parameters Usage

If you create a stored procedure that uses defaults for parameters, and a user issues the stored procedure, but misspells the parameter name, SAP ASE executes the stored procedure using the default value and does not issue an error message.

For example, if you create the following procedure:
create procedure test @x int = 1
as select @x

It returns the following:

exec test @x = 2
However, if you pass this stored procedure an incorrect parameter, it returns an incorrect result set, but does not issue a error message:
exec test @z = 4
(1 row affected)
(return status = 0)