update 表名
    set text类型字段名=replace(convert(varchar(8000),text类型字段名),'要替换的字符','替换成的值')

update 表名
    set ntext类型字段名=replace(convert(nvarchar(4000),ntext类型字段名),'要替换的字符','替换成的值')

declare @pos int
    declare @len int
    declare @str nvarchar(4000)
    declare @des nvarchar(4000)
    declare @count int
   set @des ='<requested_amount+1>'--要替换成的值

   set @len=len(@des)
   set @str= '<requested_amount>'--要替换的字符


   set @count=0--统计次数.


    WHILE 1=1
   BEGIN
       select @pos=patINDEX('%'+@des+'%',propxmldata) - 1
       from 表名
       where 条件

      IF @pos>=0
      begin
           DECLARE @ptrval binary(16)
          SELECT @ptrval = TEXTPTR(字段名)
          from 表名
          where 条件
           UPDATETEXT 表名.字段名 @ptrval @pos @len @str
          set @count=@count+1
       end
      ELSE
         break;
   END

   select @count


    Alter Table tbl Add newcol ntext null
     go
    update tbl set newcol=col
     go
     EXEC sp_rename 'tbl.col', 'oldcol', 'COLUMN'
     go
     EXEC sp_rename 'tbl.newcol', 'col', 'COLUMN'
     go
    alter table tbl drop column oldcol
     go

PRINT 'Refreshing all views...'

    DECLARE @vName sysname

    DECLARE refresh_cursor CURSOR FOR
    SELECT Name from sysobjects WHERE xtype = 'V'
    order by crdate
   FOR READ ONLY
    OPEN refresh_cursor

    FETCH NEXT FROM refresh_cursor
   INTO @vName
     WHILE @@FETCH_STATUS <> -1
    BEGIN
         exec sp_refreshview @vName
        PRINT '视图' + @vName + ' refreshed'
        FETCH NEXT FROM refresh_cursor
       INTO @vName
    END
    CLOSE refresh_cursor
    DEALLOCATE refresh_cursor