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(SUM(IF(type="no_completed",1,0))/COUNT(send_id),3)
FROM email e
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
