+----+----------
| id | name
+----+----------
|  1 | Boggs
|  2 | Mattingly
|  3 | Judge
|  4 | Martinez
|  5 | Rodriguez

+----+----------+-----------+
| id | player_id |   position
+----+----------+-----------+
|  1 | 1        | Pitcher
|  2 | 1        | Third Base
|  3 | 2        | First Base
|  4 | 3        | Second Base
|  5 | 3        | Pitcher

select id from Player where id not in (select player_id from Position)