MariaDB：SQL 删除不同时间戳之间的重复项

Question

我有以下 table 并且想要删除最旧和最新时间戳之间的重复项。

timestamp	type	state
2019-10-01 04:51:42	mod	off
2019-10-01 04:54:42	mod	off
2019-10-01 04:56:42	mod	off
2019-10-01 05:01:42	mod	on
2019-10-01 05:21:42	mod	on
2019-10-01 05:30:42	mod	on
2019-10-01 05:43:42	mod	off
2019-10-01 05:51:42	mod	off
2019-10-01 06:02:42	mod	off
2019-10-01 06:05:42	mod	off
2019-10-01 06:10:42	mod	on
2019-10-01 06:15:42	mod	on
2019-10-01 06:25:42	mod	on

这是我想要的通用 SQL 语句的结果。如果状态更改，我需要第一个时间戳。

timestamp	type	state
2019-10-01 04:51:42	mod	off
2019-10-01 05:01:42	mod	on
2019-10-01 05:43:42	mod	off
2019-10-01 06:10:42	mod	on

感谢您的帮助:-)

Answer 1

看到这个DBFIDDLE

SELECT `timestamp`,type,state
FROM (
  SELECT 
    `timestamp`,
    type,
    state,
    LEAD(state) OVER (ORDER BY `timestamp`) as Next,
    LAG(state) OVER (ORDER BY `timestamp`) as Previous
  FROM t1
  ) x
WHERE state=Next AND (state<>Previous OR Previous is null);

MariaDB：SQL 删除不同时间戳之间的重复项

MariaDB: SQL to remove duplicates between different timestamps

mysql

sql

duplicates

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