如何通過內部聯接表排序

Question

我有4張桌子。 這是我的代碼

SELECT * FROM reservation AS t1 INNER JOIN guest AS t2
ON t1.guest_id = t2.guest_id 
INNER JOIN room AS t3 
ON t1.room_id = t3.room_id 
INNER JOIN room_type AS t4
ON t3.room_type_id = t4.room_type_id

如何在desc中按此順序訂購？ 非常感謝 ：）

Answer 1

SELECT * FROM reservation AS t1 INNER JOIN guest AS t2
ON t1.guest_id = t2.guest_id 
INNER JOIN room AS t3 
ON t1.room_id = t3.room_id 
INNER JOIN room_type AS t4
ON t3.room_type_id = t4.room_type_id 
order by t1.guest_id desc

Answer 2

 SELECT * FROM reservation AS t1 INNER JOIN guest AS t2
 ON t1.guest_id = t2.guest_id 
 INNER JOIN room AS t3 
 ON t1.room_id = t3.room_id 
 INNER JOIN room_type AS t4
 ON t3.room_type_id = t4.room_type_id
 ORDER BY t1.reservation_datetime DESC

這就是您要問的內容，但是本專欄從何而來？

Answer 3

根據您的評論，您只需要添加ORDER BY DESC [COLUMN] 。

那應該解決您的問題。

SELECT * FROM reservation AS t1
INNER JOIN guest AS t2
ON t1.guest_id = t2.guest_id 
INNER JOIN room AS t3 
ON t1.room_id = t3.room_id 
INNER JOIN room_type AS t4
ON t3.room_type_id = t4.room_type_id
ORDER BY t1.reservation_datetime DESC

我建議您以更易記憶的方式命名變量，這樣我會更容易分析，例如SELECT * FROM reservation AS r Reservation SELECT * FROM reservation AS r

Answer 4

SELECT * FROM reservation AS t1 
INNER JOIN guest AS t2 ON t1.guest_id = t2.guest_id 
INNER JOIN room AS t3 ON t1.room_id = t3.room_id 
INNER JOIN room_type AS t4 ON t3.room_type_id = t4.room_type_id
ORDER BY t1.reservation_datetime DESC

但要確保

• 預留表中必須有列名Reservation_datetime
• guest_id列應出現在預訂表和來賓表中
• 房間表和預訂表中必須存在room_id列
• room_type_id列必須存在於room表和room_type表中