declare @t table(ID ntext)
insert into @t select 'asf'
select ID =cast(ID as nvarchar) + cast('123456' as nvarchar) from @t

------解决方案--------------------
SQL code
create table T(Name text)
go
insert T select 'aaaa'

----2000支持8000个字符，2005用nvarcahr(max)/varchar(max)--与text大小一样
update T
set Name=cast(Name as varchar(8000))+'123'
from 
    T

select * from T


aaaa123

（所影响的行数为 1 行）

------解决方案--------------------
SQL code
create table T(Name text)
go
insert T select 'aaaa'


SQL2000text大于8000:

declare test cursor for
select textptr(Name)  from T 
declare @p binary(16)
open test
fetch next from test into @p
while @@fetch_status=0
begin
    updatetext T.Name @p null 0 '1234'
    fetch next from test into @p
end
close test
deallocate test
go

select * from T

aaaa1231234

（所影响的行数为 1 行）