拉链表

select * from  order_info_20210726;--快照，
select * from ORDER_INFO_DZ ;--拉链表

--重跑
delete from order_info_dz where date_id='2020-09-13'
--第一次加工初始化所有数据
insert into  order_info_dz
  select a.order_id,
         a.order_status,
         a.create_time,
         a.update_time,
         substr(a.update_time,0,10),
         '9999-12-31',
         '2020-09-10'
from order_info_20210726 a
--抽取更新及当天新增数据
insert into order_info_dz
  select a.order_id,
         a.order_status,
         a.create_time,
         a.update_time,
         a.start_dt,
         --a.end_dt,
         --b.order_id ,
         case when a.end_dt ='9999-12-31' and b.order_id is not null
           then a.date_id else a.end_dt end,
           '2020-09-11'
from order_info_dz a 
left join order_info_20210726 b
on a.order_id=b.order_id
where a.date_id='2020-09-10'
union all 
  select a.order_id,
         a.order_status,
         a.create_time,
         a.update_time,
         substr(a.update_time,0,10),
         '9999-12-31',
         '2020-09-11'
from order_info_20210726 a

--查看当前所有有效记录
select * from order_info_dz b where b.end_dt='9999-12-31' and date_id='2020-09-11'
--查看9月10日快照
select *
  from order_info_dz m
 where m.date_id = '2020-09-10'
   and m.start_dt <= '2020-09-10'
   and end_dt>='2020-09-10';
   
--查看9月11日快照
select *
  from order_info_dz m
 where m.date_id = '2020-09-11'
   and m.start_dt <= '2020-09-11'
   and end_dt>='2020-09-11';