题解 | #牛客每个人最近的登录日期(一)#

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