解决方法：

select date‘2014-06-01‘+rownum-1 as my_numbers
from dual
connect by level <= (date‘2014-07-01‘ - date‘2014-06-01‘) + 1

date 和to_date功能一样

select to_date(‘2014-06-01‘,‘yyyy-mm-dd‘)+rownum-1 as my_numbers
from dual
connect by level <= (to_date(‘2014-07-01‘,‘yyyy-mm-dd‘) - to_date(‘2014-06-01‘,‘yyyy-mm-dd‘)) + 1