Question

编写此查询的正确方法是什么？

String squery= "update Room set GuestCode="+gc+", FirstName=(select FirstName from GuestDetails where GuestCode="+gc+"), LastName=(select LastName from GuestDetails where GuestCode="+gc+"), Country=(select Country from GuestDetails where GuestCode="+gc+"), State=(select State from GuestDetails where GuestCode="+gc+"), City=(select City from GuestDetails where GuestCode="+gc+"), ContactNo=(select ContactNo from GuestDetails where GuestCode="+gc+") where RoomNo="+rn+"";

我正在尝试在另一个表（GuestDetails）中使用guestcode作为输入在表（Room）中设置一些值。我在子查询中获得异常作为无效的memo，ole或超链接对象。请帮忙。

Answer 1

这可能是编写更新的更好方式。这适用于sql server

UPDATE A
SET    GuestCode = 'gc',
       FirstName = B.FirstName,
       LastName = B.LastName,
       Country = Country,
       State = B.State,
       City = B.City,
       ContactNo = B.contactNO
FROM   ROOM A
       JOIN GuestDetails B
         ON b.GuestCode = 'gc'
WHERE  RoomNo = 'rn';

Answer 2

最好使用存储过程来避免sql注入。您的代码易受注射攻击。

还可以使用连接来避免由于性能问题而进行的子选择。

在另一个表中设置表中的值

2 个答案: