题解 | 2021年11月每天的人均浏览文章时长
SELECT DATE(in_time) AS dt, ROUND(SUM(TIMESTAMPDIFF(second, in_time, out_time)) / COUNT(DISTINCT uid), 1) AS avg_viiew_len_sec FROM tb_user_log WHERE artical_id != 0 AND YEAR(in_time) = 2021 AND MONTH(in_time) = 11 GROUP BY DATE(in_time) ORDER BY avg_viiew_len_sec;