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