EASIEST SOLUTION

select c.company_code, c.founder ,count(DISTINCT l.lead_manager_code),

count(DISTINCT s.senior_manager_code) ,count(DISTINCT m.manager_code),

count(DISTINCT e.employee_code)

from company c

join lead_manager l on c.company_code = l.company_code

join Senior_Manager s on l.lead_manager_code = s.lead_manager_code

join manager m on s.Senior_Manager_code = m.senior_manager_code

join employee e on m.manager_code = e.manager_code

group by c.company_code , c.founder

order by c.company_code;