问如何在甲骨文中获得Date_Difference月，几天？

EN

SQL> with
  2  test (start_date, end_date) as
  3    (select date '2020-10-01',
  4            date '2020-11-02'
  5     from dual
  6    ),
  7  calendar as
  8    (select start_date + level - 1 datum
  9     from test
 10     connect by level <= end_date - start_date + 1
 11    )
 12  select to_char(datum, 'yyyy.mm') month,
 13         count(*) days
 14  From calendar
 15  group by to_char(datum, 'yyyy.mm')
 16  order by 1;

MONTH         DAYS
------- ----------
2020.10         31
2020.11          2

SQL>

with cte (start_date, end_date) as (
  select date '2020-10-01', date '2020-11-02' from dual
),
rcte (start_date, end_date, part_month) as (
  select start_date, end_date, trunc(start_date, 'MM')
  from cte
  union all
  select start_date, end_date, part_month + interval '1' month
  from rcte
  where part_month < trunc(end_date, 'MM')
)
select extract(month from part_month) as month_num,
  least(end_date, last_day(part_month))
    - greatest(start_date, part_month)
    + 1 as num_days
from rcte
order by part_month;