MySQL 8.0

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select version();


version()


8.0.27


create table tab (patient varchar(10), visit int, physician varchar(10));
insert into tab values
('a', 1, 'id_1'),
('a', 2, 'id_2'),
('a', 3, 'id_1'),
('a', 4, 'id_3'),
('b', 5, 'id_1'),
('b', 6, 'id_2'),
('c', 7, 'id_1'),
('c', 8, 'id_2'),
('c', 9, 'id_3');
select * from tab;


patient
visit
physician


a
1
id_1

a
2
id_2

a
3
id_1

a
4
id_3

b
5
id_1

b
6
id_2

c
7
id_1

c
8
id_2

c
9
id_3


select patient, visit 
  from (select patient, visit, row_number() over (partition by patient order by visit) rn
          from  (select patient, min(visit) as visit from tab group by patient, physician) t1
       ) t2
  where t2.rn = 3


patient
visit


a
4

c
9