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(sum(if(type
='no_completed',1,0)) / sum(if(type
='completed',1,1)),3)
FROM email
WHERE send_id NOT IN(select id FROM user
where is_blacklist = 1)
and receive_id NOT IN(select id FROM user
where is_blacklist = 1)
GROUP BY date