有一个字段的默认值是根据ID来变化的,怎么实现?

[blacklevin]

例如三个字段
ID 主键
AAA int
BBB varchar(50)

在插入新行时
如果AAA为1时,BBB的值是 "ttt"+ID
如果AAA为2时,BBB的值是 "sss"+ID

怎么实现?
是不是一定要先插入行,取出ID,再更新这一行?

[liangpei2008]

用开关语句CASE实现

[a97191]

做个if判断或才用case语句

[blacklevin]

写在什么地方?
楼上能书详细点吗

[liangpei2008]

create table t1 (ID int,AAA int,bbb varchar(50))
--------------
CREATE TRIGGER Test5
ON t1
FOR insert
AS
declare @a int
if update(AAA)
select @a=AAA from inserted
if @a=1
Update A
set BBB='ttt'+cast(A.ID as varchar(10))
from T1 A,Inserted B
where A.id=B.id
else
Update A
set BBB='sss'+cast(A.ID as varchar(10))
from T1 A,Inserted B
where A.id=B.id
-------------Try

insert into t1(id,AAA)
select 1,1