【大厂真题】SQL26题解 | 请写出计算粉丝ctr的sql语句
# 通过
SELECT SUM(read_num)/SUM(show_num) as fans_ctr
from c
inner join
(
SELECT b.content_id as content_id1,a.fans_id as fans_id1
FROM b
LEFT JOIN
a # 多了from
on b.author_id=a.author_id
) t
on c.content_id=t.content_id1
and c.fans_id=t.fans_id1
