sql - ASP C# 查询删除内部连接表

Question

我有此代码用于更新，但如何将其更改为 DELETE 不更新。这可能吗？

update r set r.Status = 'Checked-in' from Reservation r 
inner join GuestInfo g on g.GuestID = r.GuestID 
where g.GuestFName = 'firstname' 
and g.GuestLName = 'lastname' 
and r.RoomNo = '103'

Answer 1

像这样的东西应该工作：

delete r from Reservation r 
inner join GuestInfo g on g.GuestID = r.GuestID 
where g.GuestFName = 'firstname' 
and g.GuestLName = 'lastname' 
and r.RoomNo = '103'

Answer 2

Delete from Reservation
where id in 
(select r.id from Reservation r 
inner join GuestInfo g on g.GuestID = r.GuestID 
where g.GuestFName = 'firstname' 
and g.GuestLName = 'lastname' 
and r.RoomNo = '103')

Answer 3

绝对地！您可以简单地摆脱这些UPDATE部分并将关键字更改为DELETE：

delete Reservation
from Reservation r 
    inner join GuestInfo g on g.GuestID = r.GuestID 
where g.GuestFName = 'firstname' 
and g.GuestLName = 'lastname' 
and r.RoomNo = '103'

事实上，这很常见。有很多时候你需要DELETE根据条件做一个更复杂的，而且很多时候 SELECT和UPDATE语句可以很容易地变成一个DELETE. 事实上，我曾经工作过的一个地方，他们的规则是这样的：

编写SELECT语句，然后如果它为您获取数据，请摆脱SELECT并将其更改为DELETE-但只有这样。