题解 | 牛客每个人最近的登录日期(六)
牛客每个人最近的登录日期(六)
https://www.nowcoder.com/practice/572a027e52804c058e1f8b0c5e8a65b4
-- 首先注意读题，是累加（这里就确认要用窗口函数了),然后题目提到有登录却没有刷题的哪一天的数据不需要输出，那么证明这个题就主要用user表和passing_number表
SELECT
t2.name u_n,
t1.date AS date,
SUM(t1.number) OVER(partition by t1.user_id order by t1.date) ps_num
FROM passing_number t1
LEFT JOIN user t2
ON t1.user_id = t2.id
ORDER BY t1.date,t2.name
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