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