create table tbtext(id int,name text)
insert tbtext select 1,'a'

DECLARE @ptrval binary(16),@len int
SELECT @ptrval = TEXTPTR(name) 
   FROM tbtext where id=1

UPDATETEXT tbtext.name @ptrval 1 null 'b';


select * from tbtext

------解决方案--------------------
麻烦大了,下面引用邹建写的:
SQL code

 --下面的代码演示,   如果把两个   text   列相加,   更新到其中一个   text   列中   
  USE   tempdb   
  GO   
    
  --   测试环境   
  CREATE   TABLE   ta(id   int   identity(1,   1),   col1   text)   
  CREATE   TABLE   tb(id   int   identity(1,   1),   col1   text)   
  INSERT   ta   SELECT   REPLICATE('abc',   8000)   
  INSERT   tb   SELECT   REPLICATE('cba',   8000)   
    
  --   show   insert   data   length   
  SELECT   [ta.col1]   =   DATALENGTH(col1)   FROM   ta   
  SELECT   [tb.col1]   =   DATALENGTH(col1)   FROM   tb   
  GO   
    
  --   更新   ta,   让   ta.col1   =   ta.col1   +   '   '   +   tb.col1   
  --                     条件:   ta.id   =   1,   tb.id   =   1   
  DECLARE   @p1   binary(16),   @p2   binary(16)   
    
  SELECT   @p1   =   TEXTPTR(col1)   FROM   ta   (NOLOCK)   
  WHERE   id   =   1   
  IF   TEXTVALID('ta.col1',   @p1)   =   0   
  BEGIN   
          RAISERROR('ta.col1   invalid',   16,   1)   
          RETURN   
  END   
    
  SELECT   @p2   =   TEXTPTR(col1)   FROM   tb   (NOLOCK)   
  WHERE   id   =   1   
  IF   TEXTVALID('tb.col1',   @p2)   =   0   
  BEGIN   
          RAISERROR('tb.col1   invalid',   16,   1)   
          RETURN   
  END   
    
  --   insert   space   split   
  UPDATETEXT   ta.col1   @p1   NULL   0   '-'   
    
  --insert   tb.col1   
  UPDATETEXT   ta.col1   @p1   NULL   0   tb.col1   @p2   
  GO   
    
  --   show   update   result   
  SELECT   [ta.col1]   =   SUBSTRING(col1,   1,   10)   +   '...'   +   SUBSTRING(col1,   15988,   100),     
          [ta.col1_length]=   DATALENGTH(col1)   
  FROM   ta   
  WHERE   id   =   1   
  GO   
    
  DROP   TABLE   ta,   tb

------解决方案--------------------
学习了。。。

------解决方案--------------------
SQL code
if object_id('tbtext') is not null 
drop table tbtext
go
create table tbtext(id int,name text)
insert tbtext 
select 1,'a' union all 
select 2,'cc'

DECLARE @ptrval binary(16),@len int
SELECT @ptrval = TEXTPTR(name) ,@len=DATALENGTH(name)
   FROM tbtext where id=2

UPDATETEXT tbtext.name @ptrval @len 0 'b';

 
select id,convert(varchar(max),name) name from tbtext
/*
id          name
----------- ----------------------------------------------------------------------------------------------------------------
1           a
2           ccb

(2