使用expiredate

Question

我需要建立一种基于桌子的som历史 id和日期

每个日期都标志着一个变化和最新的日期 活跃的，

table

historic_trans
id  trans_date  
22  20170510 
22  20170502 
22  20170412

我想建立一个最新行的历史表 通过添加过期列作为＆＃39; 99991231＆＃39;

来获得活跃标记

我可以通过

轻松找到活跃的

select id, max(trans_date)trans_date, '99991231' as Expiredate, 'yes' as active
from historic_trans 
where id = '22'
group by id

但我真的需要在前一行设置trans_date  在我的非活动行

id  trans_date   Expiredate active 
22  20170510    99991231    yes
22  20170502    20170510    no
22  20170412    20170502    no 

因此expiredate反映了交易的变化

可以在纯hql / sql

中完成

我一直在玩以下代码，但我被困在其中

select historic_trans.id, historic_trans.trans_date,
    case when aktiv.Expiredate = '99991231' then aktiv.Expiredate
     else aktiv.Expiredate
    end as Expiredate
 from historic_trans 
 left outer join 
(
 select id, max(trans_date)trans_date, '99991231' as Expiredate, 'yes' as active
    from historic_trans 
    where id = '22' 
 group by id
) aktiv on aktiv.id = historic_trans.id and aktiv.trans_date =   historic_trans.trans_date
 where historic_trans.id = '22'  

有什么建议吗？

Answer 1

select  id
       ,trans_date
       ,lag (trans_date,1,date '9999-12-31') over w                     as Expiredate
       ,case when row_number () over w = 1 then 'yes' else 'no' end     as active

from    historic_trans

window  w as (partition by id order by trans_date desc)
;

+----+------------+------------+--------+
| id | trans_date | expiredate | active |
+----+------------+------------+--------+
| 22 | 2017-05-10 | 9999-12-31 | yes    |
| 22 | 2017-05-02 | 2017-05-10 | no     |
| 22 | 2017-04-12 | 2017-05-02 | no     |
+----+------------+------------+--------+