题解 | 请写出计算粉丝ctr的sql语句
请写出计算粉丝ctr的sql语句
https://www.nowcoder.com/practice/853a6567cf524f63bab0879b8d0bfe62
select sum(read_num)/sum(show_num) fans_ctr from c left join b using(content_id) right join a on a.author_id=b.author_id and a.fans_id=c.fans_id