MariaDB 10.3

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select version();


version()


10.3.36-MariaDB-1:10.3.36+maria~deb10-log


CREATE TABLE dataset ( 
 `ItemID` INT,
 `ItemName` VARCHAR(10),
 `Value` INT,
 `Timestamp` TIMESTAMP
);

INSERT INTO dataset VALUES
('1', 'A', '22', '2021-12-22 20:01:00'),
('1', 'A', '2', '2021-12-22 15:09:44'),
('1', 'A', '3', '2021-12-22 14:39:49'),
('2', 'B', '54', '2021-12-22 12:46:37'),
('2', 'B', '23', '2021-12-22 12:17:52'),
('2', 'B', '43', '2021-12-22 11:19:11'),
('1', 'A', '23', '2021-12-22 04:00:58'),
('1', 'A', '53', '2021-12-22 03:00:58'),
('3', 'C', '21', '2021-12-21 04:00:58'),
('2', 'B', '74', '2021-12-21 04:06:58'),
('2', 'B', '36', '2021-12-21 04:06:09'),
('1', 'A', '34', '2021-12-21 03:08:09');

Records: 12  Duplicates: 0  Warnings: 0


WITH ordered AS (
  SELECT 
    *, 
    LAG(`ItemID`) OVER (ORDER BY `Timestamp` DESC) AS LastItem
  FROM dataset
)
SELECT `ItemID`, `ItemName`, `Value`, `Timestamp`
FROM ordered
WHERE `ItemID` <> `LastItem` OR `LastItem` IS NULL
ORDER BY `Timestamp` DESC


ItemID
ItemName
Value
Timestamp


1
A
22
2021-12-22 20:01:00

2
B
54
2021-12-22 12:46:37

1
A
23
2021-12-22 04:00:58

2
B
74
2021-12-21 04:06:58

3
C
21
2021-12-21 04:00:58

1
A
34
2021-12-21 03:08:09

ItemID	ItemName	Value	Timestamp
1	A	22	2021-12-22 20:01:00
2	B	54	2021-12-22 12:46:37
1	A	23	2021-12-22 04:00:58
2	B	74	2021-12-21 04:06:58
3	C	21	2021-12-21 04:00:58
1	A	34	2021-12-21 03:08:09