You can use a conditional function call to handle null values for non-nullable parameters. The following example uses a case expression:
select name, case when jobcode is not null then job_of(jobcode) else null end from sales_emps where case when jobcode is not null then job_of(jobcode) else null end <> “Admin”
In this example, we assume that the function job_of was created using the default clause called on null input.
