Question

单一更新工作：

UPDATE users SET email=@newemail WHERE email=@oldemail
(1 Zeile(n) betroffen)

Double UPDATE无效：

UPDATE users SET email=@newemail WHERE email=@oldemail, alternateEmail=@newemail WHERE alternateEmail=@oldEmail
Meldung 102, Ebene 15, Status 1, Zeile 1
Incorrect syntax near ','.

如何在单个语句中执行此操作（即使我要检查N列）？

澄清：如果我有桌子

email     alternateEmail
a@b.c     d@e.f
d@e.f     a@b.c

我设置了@oldemail='a@b.c'，@newemail='g@h.i'，结果表应为

email     alternateEmail
g@h.i     d@e.f
d@e.f     g@h.i

我知道我可以在2（或N）个陈述中做到这一点：

UPDATE users SET email=@newemail WHERE email=@oldemail
UPDATE users SET alternateEmail=@newemail WHERE alternateEmail=@oldEmail

但是我可以在一个声明中这样做吗？

Answer 1

你可以这样做：

UPDATE users SET 
    email = case 
               when email = @oldemail then @newemail 
               else email 
            end,
    alternateEmail = case 
                       when alternateEmail = @oldemail then @newemail 
                       else alternateEmail 
                     end
where 
    email = @oldemail 
    or alternateEmail = @oldemail

将值A更改为B，无论它在哪个列中

1 个答案: