# 注意,这一题是新用户的次日留存率 并且是计算每一天 # 首先是考虑 新用户 (新用户可以通过第一次登陆的时间来判断) 然后是考虑 留存率 with t1 as ( select distinct user_id, date, first_value(date) over (partition by user_id order by date asc rows between unbounded preceding and unbounded following) as first_date, lead(date, 1...