题解 | #牛客直播转换率#
牛客直播转换率
http://www.nowcoder.com/practice/73bf143cfc7f452a8569c6d7eca380f9
select t1.*,t2.rate from (select course_id,course_name from course_tb)t1 left join (select course_id,round((sum(if_sign)/sum(if_vw)) *100,2) rate FROM behavior_tb group by course_id)t2 on t1.course_id=t2.course_id order by course_id