当TableA中的ColumnA根据两个表中的公共列更新时，编写一个触发器来更新TableB中的columnB

Question

CREATE TABLE [dbo].[USERS]
(
    [USER_NAME] [nvarchar](64) NOT NULL,
    [EMAIL_ADDRESS] [nvarchar](256) NULL,
    [REGISTERED_DATE] [datetime] NOT NULL,
    [FULL_NAME] [nvarchar](256) NOT NULL,
    [MANAGER] [nvarchar](64) NULL,
    [DEPARTMENT] [nvarchar](256) NULL,
    [TITLE] [nvarchar](64) NULL,

    PRIMARY KEY CLUSTERED ([USER_NAME] ASC)
                WITH (PAD_INDEX = OFF, STATISTICS_NORECOMPUTE = OFF, 
                      IGNORE_DUP_KEY = OFF, ALLOW_ROW_LOCKS = ON, 
                      ALLOW_PAGE_LOCKS = ON) ON [PRIMARY]
) ON [PRIMARY]

这是我的表，我希望在更新管理器列时触发触发器，并且必须根据USER_NAME列在另一个表上更新相同的管理值。

我尝试了下面的触发器，但它不起作用。

Create TRIGGER [dbo].[UpdateManager]
ON  [dbo].[USERS]
AFTER UPDATE
AS 
BEGIN

SET NOCOUNT ON;

declare @USER_NAME as nvarchar   
declare @MANAGER as nvarchar
if(update(MANAGER))
begin
    select @USER_NAME = USER_NAME from deleted
    select @manager = Manager from deleted 
    update [dbo].[USERS_TEST] set MANAGER=@MANAGER where USER_NAME=  @USER_NAME     

end

END

Answer 1

您的触发器中有两个主要问题：

• 如评论中所述， deleted可以有多行，您没有考虑到这一点。
• nvarchar没有长度； 在这种情况下，默认长度为 1。

我怀疑您想要的查询是：

update ut
    set MANAGER = d.MANAGER 
    from [dbo].[USERS_TEST] ut join
         deleted d
         on ut.USER_NAME = d.USER_NAME  ;