SQL 67) 查询每个用户最近一天登录的日子，用户的名字，设备的名字

方法）WHERE子句筛选最晚日期

• 查询结果按照user的name升序排序

  SELECT u.name AS u_n ,c.name AS c_n ,l.date
  FROM login l
  JOIN user u ON l.user_id = u.id
  JOIN client c ON l.client_id=c.id
  WHERE (l.user_id,l.date)IN(
    SELECT user_id, MAX(date) 
    FROM login
    GROUP BY user_id)
  ORDER BY u_n;