题解 | #异常的邮件概率#
异常的邮件概率
https://www.nowcoder.com/practice/d6dd656483b545159d3aa89b4c26004e
select date,round(count(if(type='no_completed',1,null))/count(type),3) from email where send_id in(select id from user where is_blacklist=0) and receive_id in(select id from user where is_blacklist=0) group by date order by date;