使用connect by生成时间列表的方法

生成年份列表
select 1949 + rownum - 1 as year
  from dual
connect by 1949 + rownum - 1 <= to_char(sysdate, 'yyyy')
 order by year desc

生成月份列表
select to_char(add_months(to_date('2000-01','yyyy-mm'), rownum - 1), 'yyyymm') as month
  from dual
connect by add_months(to_date('2000-01','yyyy-mm'), rownum - 1) <= trunc(sysdate, 'mm')
 order by month desc

生成天列表
select to_char(to_date('2007-12-01','yyyy-mm-dd') + rownum - 1, 'yyyymmdd') as day
  from dual
connect by to_date('2007-12-01','yyyy-mm-dd') + rownum - 1 <= trunc(sysdate)
 order by day desc

生成小时列表
select to_char(to_date('2007-12-27','yyyy-mm-dd') + (rownum - 1) / 24, 'yyyymmddhh24') as hour
  from dual
connect by to_date('2007-12-27','yyyy-mm-dd') + (rownum - 1) / 24 <=
           trunc(sysdate,'hh24')
 order by hour desc