题解 | 请写出计算粉丝ctr的sql语句

简单思路，多表连接，根据题目要求写连接条件，最后作为临时表或者子查询，在主查询中计算粉丝ctr；

with integration as(
    select b.author_id,
           b.content_id,
           a.fans_id,
           c.show_num,
           c.read_num
    from a left join b
    on a.author_id = b.author_id
    join c
    on a.fans_id = c.fans_id
    and b.content_id = c.content_id
)
select sum(read_num)/sum(show_num) as fans_ctr
from integration