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;

1、找到用户id及其对应的最大日期

WHERE (l.user_id, l.date) IN (
        SELECT user_id,MAX(date)
        FROM login
        GROUP BY user_id
        )

2、联合三张表

FROM
    login l
    JOIN user u ON l.user_id = u.id
    JOIN client c ON l.client_id = c.id

3、按用户id（姓名）进行groupby输出

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;