oracle 日期吧一位转换成两位

select  *
       to_char(to_date(t.f_vc_day || '-' || t.f_vc_month || '月' || '-' ||
                       t.f_vc_year),
               'yyyymmdd') || to_char(to_date(t.f_vc_time, 'hh24'), 'hh24')
  from B
group by to_char(to_date(t.f_vc_day || '-' || t.f_vc_month || '月' || '-' ||
                          t.f_vc_year),
                  'yyyymmdd') ||
          to_char(to_date(t.f_vc_time, 'hh24'), 'hh24');