题解 | #牛客直播转换率#

select
    ct.course_id,
    course_name,
    ROUND((COUNT(IF(if_sign = 1, 1, NULL)) / COUNT(if_vw)) * 100, 2) AS sign_rate
from
    course_tb as ct
    join behavior_tb as bt on ct.course_id = bt.course_id
group by
    ct.course_id,
    course_name
order by
    ct.course_id asc;