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 t1.name AS u_n,
t2.name AS c_n,
t.date AS date
FROM login AS t, user AS t1, client AS t2,
(
SELECT user_id,
MAX(date) AS max_date
FROM login
GROUP BY user_id
) AS t3
WHERE
t1.id = t.user_id -- 匹配姓名
AND t2.id = t.client_id -- 匹配客户端
AND t.date = t3.max_date -- 筛选最近登陆日期
AND t.user_id = t3.user_id
ORDER BY t1.name
t2.name AS c_n,
t.date AS date
FROM login AS t, user AS t1, client AS t2,
(
SELECT user_id,
MAX(date) AS max_date
FROM login
GROUP BY user_id
) AS t3
WHERE
t1.id = t.user_id -- 匹配姓名
AND t2.id = t.client_id -- 匹配客户端
AND t.date = t3.max_date -- 筛选最近登陆日期
AND t.user_id = t3.user_id
ORDER BY t1.name
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