MySQL 5.6

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CREATE TABLE tablename (
  `id` INTEGER,
  `country` VARCHAR(8),
  `col1` INTEGER,
  `col2` INTEGER,
  `col3` INTEGER
);

INSERT INTO tablename
  (`id`, `country`, `col1`, `col2`, `col3`)
VALUES
  ('1', 'country1', '1', '2', '3'),
  ('2', 'country1', '2', '2', '1'),
  ('3', 'country1', '1', '3', '2'),
  ('4', 'country2', '3', '2', '2'),
  ('5', 'country2', '3', '3', '3'),
  ('6', 'country3', '3', '2', '2'),
  ('7', 'country3', '3', '1', '1');
select * from tablename
where id in (select max(id) from tablename group by country)


id
country
col1
col2
col3


3
country1
1
3
2

5
country2
3
3
3

7
country3
3
1
1


select t.* from tablename t
where not exists (
  select 1 from tablename
  where country = t.country and id > t.id
);


id
country
col1
col2
col3


3
country1
1
3
2

5
country2
3
3
3

7
country3
3
1
1