يا اخوان _{بدي  department nam و مجموع ال رواتب لكل قسم وعدد الموظفين بكل قسم}

ممكن بالطريقة دية

بس دية مش حتظهر قيم ال NULL

select department_name,sum(salary) "total salary",count(employee_id) "total employees" 
from employees e join departments d 
on e.department_id = d.department_id 
group by department_name;

لو عايز القيم ال null تظهر نستخدم outer join

select department_name,sum(salary) "total salary",count(employee_id) "total employees" 
from employees e full outer join departments d 
on e.department_id = d.department_id 
group by department_name;

thank youuuuuu very very much