题解 | 计算用户的平均次日留存率
计算用户的平均次日留存率
https://www.nowcoder.com/practice/126083961ae0415fbde061d7ebbde453
SELECT
COUNT(DISTINCT p.device_id,p.date)/COUNT(DISTINCT q.device_id,q.date) AS avg_ret
FROM
(SELECT DISTINCT device_id,date FROM question_practice_detail) q
LEFT JOIN
(SELECT DISTINCT device_id,date FROM
question_practice_detail) p ON q.device_id = p.device_id AND DATEDIFF(p.date,q.date)=1
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