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