解法一:窗口函数-排序函数
易错点:忘记partition by user_id
select user_id,date as d from( select user_id,date,row_number()over(partition by user_id order by date desc) as t from login ) sub where sub.t=1 order by user_id asc
解法二:窗口函数-first_value函数
FIRST_VALUE()是一个窗口函数,允许您选择窗口框架,分区或结果集的第一行
select distinct user_id,FIRST_VALUE(date) over(partition by user_id order by date desc) as d from login