题解 | #异常的邮件概率#
异常的邮件概率
https://www.nowcoder.com/practice/d6dd656483b545159d3aa89b4c26004e
select date, (sum(case when type='no_completed' then 1 else 0 end)*1.0)/count(type) 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
