select e.emp_no,e.first_name,e.last_name,e1.btype,s.salary, round((case e1.btype when 1 then s.salary*0.1 when 2 then s.salary*0.2 else s.salary*0.3 end) ,1) as bouns
from employees e,
emp_bonus e1,
salaries s
where 
e.emp_no = e1.emp_no and
e.emp_no = s.emp_no and
s.to_date = '9999-01-01' 
order by e.emp_no