MySQL 8.0

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CREATE TABLE offices
    (`building` varchar(5), `office` varchar(7))
INSERT INTO offices
    (`building`, `office`)
VALUES
    ('Seuss', 'Yertle'),
    ('Seuss', 'Cubbins'),
    ('Milne', 'Pooh'),
    ('Milne', 'Eeyore'),
    ('Milne', 'Roo')
CREATE TABLE checkins
    (`id` int, `office` varchar(7), `person` varchar(7), `timestamp` int)
INSERT INTO checkins
    (`id`, `office`, `person`, `timestamp`)
VALUES
    (1, 'Yertle', 'Aaron', 100),
    (2, 'Cubbins', 'Aaron', 200),
    (3, 'Pooh', 'Aaron', 300),
    (4, 'Cubbins', 'Charlie', 300),
    (5, 'Cubbins', 'Aaron', 700),
    (6, 'Eeyore', 'Beth', 600),
    (7, 'Pooh', 'Beth', 400)
SELECT o.building, c.person, c.id AS checkin_id, c.office, c.timestamp
FROM offices o
JOIN checkins c ON c.office = o.office
JOIN (SELECT o.building, c.person, MAX(c.timestamp) AS timestamp
      FROM offices o
      JOIN checkins c ON c.office = o.office
      GROUP BY o.building, c.person) t ON t.building = o.building AND t.person = c.person AND t.timestamp = c.timestamp
ORDER BY c.person, c.office


building
person
checkin_id
office
timestamp


Seuss
Aaron
5
Cubbins
700

Milne
Aaron
3
Pooh
300

Milne
Beth
6
Eeyore
600

Seuss
Charlie
4
Cubbins
300

building	person	checkin_id	office	timestamp
Seuss	Aaron	5	Cubbins	700
Milne	Aaron	3	Pooh	300
Milne	Beth	6	Eeyore	600
Seuss	Charlie	4	Cubbins	300