我的sql查询2个表到1个表不同的情况

Question

我有两个问题

SELECT
IF(t_booking_details.status = 1, t_room.code, (IF (t_stay_info.room IS null , t_room.code,null))) as room
FROM t_stay_info
INNER JOIN t_booking_details
ON t_stay_info.code = t_booking_details.stayInfo
RIGHT JOIN t_room
ON t_room.code = t_stay_info.room
INNER JOIN t_room_type
ON t_room_type.code = t_room.roomType
WHERE t_room_type.name = "Deluxe Double"

结果：

+-------+
| room  |
+-------+
| NULL  |
| code2 |
| code3 |
| code4 |
+-------+

SELECT 
IF(t_reservation.`status` = 1, t_room.code, (IF (t_stay_info.room IS null , t_room.code,null))) as room
FROM t_stay_info
INNER JOIN t_reservation
ON t_stay_info.code = t_reservation.stayInfo 
RIGHT JOIN t_room
ON t_room.code = t_stay_info.room 
INNER JOIN t_room_type  
ON t_room_type.code = t_room.roomType
WHERE t_room_type.name = "Deluxe Double" 

结果

+-------+
| room  |
+-------+
| code1 |
| code2 |
| code3 |
| NULL  |
+-------+

如何合并结果以便获得：

+-------+
| room  |
+-------+
| NULL  |
| code2 |
| code3 |
| NULL  |
+-------+