Funcion

CREATE OR REPLACE FUNCTION NOMBRE_DEPTO (fdepartment_id IN NUMBER)
RETURN VARCHAR2 AS
vdepartment_name departments.department_name%TYPE;
BEGIN
SELECT department_name INTO vdepartment_name
FROM departments
WHERE department_id = fdepartment_id;
RETURN vdepartment_name;
EXCEPTION
WHEN NO_DATA_FOUND THEN RETURN 'No existe Dpto';
END NOMBRE_DEPTO;

SELECT NOMBRE_DEPTO(71) FROM DUAL;