text: merge into bonuses d 
     using (select employee_id.* from employees) s 
     on (employee_id = a) 
     when not matched then insert (d.employee_id, d.bonus) 
       values (s.employee_id, s.salary)
       where (s.salary <= 8000)
     when matched then update set d.bonus = bonus 
       delete where (salary > 8000)
  
  