select a.emp_no,a.first_name,a.last_name,b.btype,c.salary,
(case
when b.btype = 1 then c.salary * 0.1
when b.btype = 2 then c.salary * 0.2
else c.salary * 0.3
end ) bonus
from employees a,emp_bonus b ,salaries c
where a.emp_no = b.emp_no
and a.emp_no = c.emp_no
and to_date='9999-01-01'