//获得日期select date from loginGROUP BY date//根据日期查询user_idSELECT DISTINCT user_idfrom LOginwhere date=(select date from loginGROUP BY date)//查询每个日期用户次日登录的用户id(包括新用户)SELECT a.user_id,a.date,b.user_id,b.datefrom login ainner joinlogin bon DAY(a.date)+1=DAY(b.date)where a.user_id=b.user_id//查询每个新用户登录的日期s...