题解 | #异常的邮件概率#
异常的邮件概率
http://www.nowcoder.com/practice/d6dd656483b545159d3aa89b4c26004e
select date, round(avg(case when type="no_completed" then 1 else 0 end),3) as p 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;