更新触发器有关问题_Sql Server

更新触发器问题
如果某个字段更新值为2，就执行这个触发器

------解决方案--------------------
你应该在触发器里面判断是否有数据行某个字段更新为２，

如楼上所说.
------解决方案--------------------
CREATE TRIGGER mytrig ON tbname FOR UPDATE
AS
if col = 2
...............
go
------解决方案--------------------
/*------------------------
create table tb(nId int identity(1,1) primary key, colForUpdate int)
go
CREATE TRIGGER uTrigOntb ON tb
AFTER UPDATE
AS
BEGIN
declare @nHasUpdateTo2 int
select @nHasUpdateTo2=count(1) from inserted I join deleted D on I.nId=D.nId
where I.colForUpdate=2 and D.colForUpdate<>2
if @nHasUpdateTo2>0
begin
print '有' + rtrim(@nHasUpdateTo2) + '行数据的colForUpdate列被改为2'
--do something else
end
END
GO

insert tb select 1
union all select 2
union all select 3
union all select 4
union all select 5
union all select 6

update tb set colForUpdate=2
where colForUpdate>=5

drop trigger uTrigOntb
drop table tb
------------------------*/

(6 row(s) affected)
有2行数据的colForUpdate列被改为2

(2 row(s) affected)

------解决方案--------------------

SQL code

create table tb(nId int identity(1,1) primary key, colForUpdate int)goCREATE TRIGGER uTrigOntb ON  tb    AFTER UPDATEAS BEGIN    declare @nHasUpdateTo2 int    select @nHasUpdateTo2=count(1) from inserted I join deleted D on I.nId=D.nId    where I.colForUpdate=2 and D.colForUpdate<>2    if @nHasUpdateTo2>0    begin        print '有' + rtrim(@nHasUpdateTo2) + '行数据的colForUpdate列被改为2'        --do something else     endENDGOinsert tb select 1union all select 2union all select 3union all select 4union all select 5union all select 6update tb set colForUpdate=2where colForUpdate>=5drop trigger uTrigOntbdrop table tb
------解决方案--------------------
create table meixiaofeng(nId int identity(1,1) primary key, colForUpdate int)
go
CREATE TRIGGER uTrigOntb ON meixiaofeng  
  AFTER UPDATE
AS  
BEGIN
declare @nHasUpdateTo2 int
select @nHasUpdateTo2=count(1) from inserted I join deleted D on I.nId=D.nId
where I.colForUpdate=2 and D.colForUpdate < >2
if @nHasUpdateTo2 >0
begin
print  '有 ' + rtrim(@nHasUpdateTo2) +  '行数据的colForUpdate列被改为2 '
--do something else  
end
END
GO

insert meixiaofeng select 1
union all select 2
union all select 3
union all select 4
union all select 5
union all select 6

update meixiaofeng set colForUpdate=2
where colForUpdate >=5