ORA-00934:Función de grupo no permitida aquí || Seleccionar MIN (Salario) del departamento mejor pagado

No puedo probar esto, pero debería funcionar:

;WITH DepartmentsSalary AS
(
    SELECT department_ID, AVG(Salary) AvgSalary, MIN(Salary) MinSalary
    FROM employees
    GROUP BY department_ID
)
SELECT department_ID, MinSalary
FROM (  SELECT department_ID, AvgSalary, MAX(AvgSalary) OVER() MaxSalary, MinSalary
        FROM DepartmentsSalary) D
WHERE MaxSalary = AvgSalary