SQL面试题：找到每个人最新的一条数据

SQL面试题：在t_score表中，找到表中每个人最近的一条分数

username	score	time
小明	98	2021-07-29
小明	90	2021-07-01
小红	96	2021-07-15
小红	100	2021-06-21
小李	95	2021-05-03

结果就应该是

username	score	time
小明	98	2021-07-29
小红	96	2021-07-15
小李	95	2021-05-03

---

两种解法：

双表联查

SELECT t1.* FROM t_score t1
INNER JOIN (SELECT username, MAX(time) AS time FROM t_score GROUP BY username) t2
ON t1.username = t2.username AND t1.time = t2.time

开窗函数(MySQL不支持)

SELECT * FROM (
SELECT *, row_number() over (partition by username order by time desc) AS rn FROM t_score
) WHERE rn = 1