some.sql

create table mc (id int, member varchar(3));

insert into mc values (1, 'abc'), (1, 'pqr'), (2, 'xyz'), (2, 'pqr'), (3, 'pqr'), (3, 'abc');

Select id,count(*) as total from mc group by id having total=(Select count(*) from mc where id=1);

-- Result:
-- +------+-------+
-- | id   | total |
-- +------+-------+
-- |    1 |     2 |
-- |    2 |     2 |
-- |    3 |     2 |
-- +------+-------+