题解 | #牛客直播转换率#

select course_id, course_name, round(sum(if_sign)/sum(if_vw)*100, 2) as 'sign_rate(%)'
from (
    select a.course_id, b.course_name, a.if_vw, a.if_sign
    from behavior_tb as a
    left join course_tb as b
    on a.course_id = b.course_id
) as c
group by course_id, course_name
order by course_id;