题解 | #牛客每个人最近的登录日期(二)#
牛客每个人最近的登录日期(二)
http://www.nowcoder.com/practice/7cc3c814329546e89e71bb45c805c9ad
SELECT u.name u_n,c.name c_n,d date
FROM login l join (
SELECT user_id,max(date) d
FROM login
GROUP BY user_id
) md
ON l.user_id = md.user_id and l.date = d
JOIN user u ON l.user_id = u.id
JOIN client c on c.id = l.client_id
ORDER BY u.name 没学到窗口函数，用简单的办法
多表连接应该比in效率高吧
