sql - 在sql中获取两个日期之间的月数和天数之间的差异

Question

我需要得到两个日期之间的差异，如果差异是 84 天，我可能应该输出 2 个月零 14 天，我刚刚给出的代码给出了总数。这是代码

SELECT Months_between(To_date('20120325', 'YYYYMMDD'),
       To_date('20120101', 'YYYYMMDD'))
       num_months,
       ( To_date('20120325', 'YYYYMMDD') - To_date('20120101', 'YYYYMMDD') )
       diff_in_days
FROM   dual; 

输出是:

NUM_MONTHS    DIFF_IN_DAYS
2.774193548       84

例如，我需要此查询的输出最差为 2 个月和 14 天，否则我不介意我是否可以在月份数字之后获得确切的天数，因为那些天数并不是真正的 14 天，因为所有月份都没有30天。

Answer 1

select 
  dt1, dt2,
  trunc( months_between(dt2,dt1) ) mths, 
  dt2 - add_months( dt1, trunc(months_between(dt2,dt1)) ) days
from
(
    select date '2012-01-01' dt1, date '2012-03-25' dt2 from dual union all
    select date '2012-01-01' dt1, date '2013-01-01' dt2 from dual union all
    select date '2012-01-01' dt1, date '2012-01-01' dt2 from dual union all
    select date '2012-02-28' dt1, date '2012-03-01' dt2 from dual union all
    select date '2013-02-28' dt1, date '2013-03-01' dt2 from dual union all
    select date '2013-02-28' dt1, date '2013-04-01' dt2 from dual union all
    select trunc(sysdate-1)  dt1, sysdate               from dual
) sample_data

结果:

|                        DT1 |                       DT2 | MTHS |     DAYS |
----------------------------------------------------------------------------
|  January, 01 2012 00:00:00 |   March, 25 2012 00:00:00 |    2 |       24 |
|  January, 01 2012 00:00:00 | January, 01 2013 00:00:00 |   12 |        0 |
|  January, 01 2012 00:00:00 | January, 01 2012 00:00:00 |    0 |        0 |
| February, 28 2012 00:00:00 |   March, 01 2012 00:00:00 |    0 |        2 |
| February, 28 2013 00:00:00 |   March, 01 2013 00:00:00 |    0 |        1 |
| February, 28 2013 00:00:00 |   April, 01 2013 00:00:00 |    1 |        1 |
|   August, 14 2013 00:00:00 |  August, 15 2013 05:47:26 |    0 | 1.241273 |

测试链接: SQLFiddle