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(q2.device_id) / COUNT(q1.device_id) AS avg_ret
FROM
(
SELECT DISTINCT
device_id,
date
FROM
question_practice_detail
) AS q1
LEFT JOIN (
SELECT DISTINCT
device_id,
date
FROM
question_practice_detail
) AS q2 ON q1.device_id = q2.device_id
AND DATEDIFF(q2.date, q1.date) = 1;
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