UPDATE中的迷糊

select * from T_CONVERT where businessid='423'  and convert_time>20101001000000 and convert_time<20101007240000

  查询出结果后要对一些特定的列进行修改，当时犯迷的地方是：认为不能根据将要修改的字段更新此字段

update t_convert set subbusiness_id =505 where subbusiness_id =506  and convert_time>'20101001000000' and convert_time<'20101007245959'