hive 库两个日期相减取年 hive两个日期相差的月份

日期格式：20200409，20190922求月份差

hive:
经过测试：
select months_between('2020-04','2019-09') from mid.dual --null
select months_between('2020-04-02','2019-09-02') from mid.dual --7
select months_between('2020-04-02','2019-09-20') from mid.dual --6.41935484
select months_between('2020-04-20','2019-09-02') from mid.dual --7.58064516


select unix_timestamp(substr(20200408,1,6),'yyyyMM') from mid.dual --1585670400
select from_unixtime(unix_timestamp(substr(20200409,1,6),'yyyyMM'),'yyyy-MM-dd') from mid.dual    --2020-04-01
最终：
select months_between(from_unixtime(unix_timestamp(substr(20200409,1,6),'yyyyMM'),'yyyy-MM-dd'),
from_unixtime(unix_timestamp(substr(20190922,1,6),'yyyyMM'),'yyyy-MM-dd')) 
from mid.dual    --7

oracle:
select to_date('202004','YYYYMM') from dual --2020/4/1
select months_between(to_date('20200402','YYYYMMdd'),to_date('20190920','YYYYMMdd')) from dual --6.41935483870968
select months_between(to_date('20200420','YYYYMMdd'),to_date('20190902','YYYYMMdd')) from dual --7.58064516129032
select months_between(to_date('202004','YYYYMM'),to_date('201909','YYYYMM')) from dual --7

 

SELECT TO_date('202004','yyyymm') FROM mid.DUAL   --2020/4/1

SELECT add_months(TO_date('202004','yyyymm'),-1) FROM mid.DUAL   --2020/3/1

SELECT TO_CHAR(add_months(TO_date('202004','yyyymm'),-1),'yyyymm') FROM mid.DUAL  --202003


select unix_timestamp('202004','yyyyMM') from mid.dual     --1585670400
select from_unixtime(unix_timestamp('202004','yyyyMM'),'yyyy-MM-dd') from mid.dual     --2020-04-01
select add_months(from_unixtime(unix_timestamp('202004','yyyyMM'),'yyyy-MM-dd'),-1) from mid.dual  --2020-03-01
select unix_timestamp(add_months(from_unixtime(unix_timestamp(sbustr('202004',1,6),'yyyyMM'),'yyyy-MM-dd'),-1),'yyyy-MM') from mid.dual  --1582992000
select from_unixtime(unix_timestamp(add_months(from_unixtime(unix_timestamp('202004','yyyyMM'),'yyyy-MM-dd'),-1),'yyyy-MM'),'yyyyMM') from mid.dual  --202003