select a.emp_no,e.first_name,e.last_name,btype,salary
,case when btype = 1 then salary* 0.1
when btype = 2 then salary* 0.2
else salary*0.3 end as bonus
from (select*from emp_bonus eb
join salaries s
on eb.emp_no = s.emp_no)a
join employees e on a.emp_no = e.emp_no
where to_date = '9999-01-01'