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
三表连接,多条件表连接。
select sum(read_num)/sum(show_num) fans_ctr from a join b on a.author_id=b.author_id join c on b.content_id=c.content_id and a.fans_id=c.fans_id
