题解 | #牛客每个人最近的登录日期(四)#
牛客每个人最近的登录日期(四)
https://www.nowcoder.com/practice/e524dc7450234395aa21c75303a42b0a
WITH T AS
(
SELECT
*
,row_number() over (partition by user_id order by `date`) rn
FROM login
)
SELECT
T.`date`
,COUNT(CASE WHEN T.RN = 1 THEN user_id END) cnt
FROM T
GROUP BY T.`date`
ORDER BY T.`date`
;