Good stuff! To raise errors/exceptions, use the RAISE EXCEPTION statement.
The example below shows how to raise an exception:
RAISE EXCEPTION 'Duplicate department_id: %', department_id;
This statement can be used anywhere in the function body. If the execution of a function encounters a RAISE EXCEPTION statement, the execution of the function is interrupted and the exception is thrown.
Amend the template function: change the logic of the function, so that an exception is raised every time a nonexistent employee ID is passed in as an argument.
For example, when we call the function like this:
SELECT get_employees_salary(-1000);
We should receive the following message:
ERROR: Nonexistent employee ID --> -1000
Go ahead and amend the function logic so it raises an exception in the following format:
Nonexistent employee ID --> %
