- max 连接的时候注意多层嵌套。
select user.name, client.name, DATE from login join user on login.user_id = user.id join client on login.client_id = client.id inner join (select user_id, max(date) ma from login group by user_id) t on t.user_id = login.user_id and t.ma = login.date order by user.name