sqlntext替换存储过程

create procedure replace_ntext 
 @table_name nvarchar(100), --目标表名 
 @field_name nvarchar(100), --目标字段名 
 @where_str nvarchar(1000), --该表主键字段名 如id=1 
 @old nvarchar(1000), --需要替换的字符串 
 @new nvarchar(1000) --替换后的字符串 
as 
begin 
 
declare @SqlStr nvarchar(4000) 
	set @SqlStr = 'declare @pos int, @len int, @count int set @count=0 set @len=len('''+@old+''') '
	set @SqlStr = @SqlStr + ' select @pos = patINDEX(''%'+@old+'%'',['+@field_name+']) - 1'+' from ['+@table_name+'] where '+ @where_str
	set @SqlStr = @SqlStr + ' while @pos>0 ' 
	set @SqlStr = @SqlStr + ' begin' 
	set @SqlStr = @SqlStr + ' declare @ptrval binary(16)' 
	set @SqlStr = @SqlStr + ' SELECT @ptrval = TEXTPTR(['+@field_name+']) from ['+@table_name+'] where '+ @where_str
	set @SqlStr = @SqlStr + ' UPDATETEXT ['+@table_name+'].['+@field_name+'] @ptrval @pos @len '''+ @new + ''''
	set @SqlStr = @SqlStr + ' select @pos = patINDEX(''%'+@old+'%'',['+@field_name+']) - 1'+' from ['+@table_name+'] where '+ @where_str
	set @SqlStr = @SqlStr + ' set @count=@count+1 '
	set @SqlStr = @SqlStr + ' end '
	set @SqlStr = @SqlStr + ' select @count'
 --print @SqlStr
 execute sp_executesql @SqlStr 
end