SQL-检查上个月是否有商品，然后标记它

Question

我正在尝试解决SQL中的问题，但到目前为止没有成功。我有一张这样的桌子：

OWNER|STORE|DATE
  A  | MIX |01/01/2019
  A  | BIX |01/01/2019
  A  | BIX |02/01/2019
  B  | CIX |01/01/2019
  B  | CIX |02/01/2019

这是一个表，显示有关所有者及其商店的信息。所有者可以在一个月内拥有一家商店，但是该商店可能在下个月消失。或者，他们的商店可能在一月开张，但二月就消失了。

我想找到一种方法来标记此商店的移动，因此，如果一月有一家商店，而二月又去了，我会标记一个列为“已消失”。如果一家商店在一月不存在，而是在二月出现，我将其标记为“新”。

有人可以帮我吗？谢谢！

Answer 1

SELECT 
    ID, 
    OWNER, 
    STORE, 
    DATE, 
    CASE WHEN DATE IN (SELECT DATE FROM TableName
WHERE DATE IN (<InsertDatesHere)) THEN 'NEW' ELSE 'Gone' END AS Flag

Answer 2

SELECT
 a.store , a.owner, max(a.timedate ), 'gone' as [flag]
FROM
  store as a
  inner  join
  (SELECT
 owner,store,timedate
FROM store) as b
on b.store = a.store and a.timedate!=b.timedate
group by a.store , a.owner

sqlfiddle here

Answer 3

使用lag()和lead()：

select t.*,
       (case when prev_date < add_months(date, -1) or
                  prev_date is null
             then 'new'
             when next_date > add_months(date, 1) or
                  next_date is null
             then 'gone'
        end) as flag
from (select t.*,
             lag(date) over (partition by owner, store order by date) as prev_date,
             lead(date) over (partition by owner, store order by date) as lead_date
      from t
     ) t;