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 c.course_id,c.course_name,b.if_vw,b.if_sign
from course_tb c join behavior_tb b on 
c.course_id = b.course_id) t group by course_id,course_name
order by course_id