Nader93

SELECT company.company_code,company.founder,
count(distinct Lead_manager.lead_manager_code),
count(distinct Senior_manager.senior_manager_code),
count(distinct Manager.manager_code),count(distinct Employee.employee_code)
from company
INNER JOIN Lead_Manager
on company.company_code = Lead_Manager.company_code

INNER JOIN Senior_Manager
on company.company_code = Senior_Manager.company_code

Nader93

select  case 
        when p is null then concat(n, ' Root')
        when n in (select distinct p from bst) then concat(n, ' Inner')
        else concat(n, ' Leaf')
    end
from bst
order by n asc

Nader93

select concat(name,"(",left(OCCUPATION,1),")")
from OCCUPATIONS
order by name asc;
select concat("There are a total of"," ",count(OCCUPATION)," ",LOWER(OCCUPATION),"s",".")
from OCCUPATIONS
group by OCCUPATION
order by count(OCCUPATION),OCCUPATION;