SQL如何從另一個表中不存在的表中選擇

Question

例如，我有2個相互關聯的表。 room_directory.id和booked_room.room_id

room_directory

id
room_number

booked_room

id
booking_id
room_id

如何編寫查詢，僅從room_directory中選擇booked_room表中不存在的房間 ？

Answer 1

select * from room_directory where id not in (select room_id from  booked_room)

Answer 2

select * from room_directory r where r.id not in (select room_id from booked_room b where r.id = b.room_id);

要么

SELECT * FROM room_directory r WHERE NOT EXISTS (SELECT * from booked_room b WHERE r.id = b.room_id);