MySQL 8.0

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CREATE TABLE tablename (
  `device_id` INTEGER,
  `section` VARCHAR(1)
);

INSERT INTO tablename
  (`device_id`, `section`)
VALUES
  ('100', 'A'),
  ('101', 'B'),
  ('102', 'B'),
  ('103', 'C'),
  ('104', 'D'),
  ('105', 'C'),
  ('106', 'A'),
  ('107', 'C');
select device_id, section
from (
  select *, row_number() over (partition by section order by rand()) rn
  from tablename
) t
where rn = 1


device_id
section


100
A

102
B

105
C

104
D


select device_id, section
from (
  select *, row_number() over (partition by section order by rand()) rn
  from tablename
) t
where rn = 1


device_id
section


100
A

102
B

105
C

104
D


select device_id, section
from (
  select *, row_number() over (partition by section order by rand()) rn
  from tablename
) t
where rn = 1


device_id
section


100
A

101
B

107
C

104
D