数据:
          indbtime
              2008-05-10 12:25:56
              2008-06-24 23:15:15
              2008-06-24 06:35:35
              2008-06-24 11:48:32
              2008-07-16 21:25:46
              2008-07-16 14:05:14 我希望按日期分组,希望得到的结果是:          indbtime
              2008-05-10
              2008-06-24
              2008-07-16请问如何实现?