重叠日期

Question

*编辑 - 无更新权。

我有下表：一个 ID 应该只关联到一个区域。 TableB 上有重叠。因此，John 在 1/9/19 与 East 和 MidEast 地区相关联。

我可以操纵 TableB 来修复重叠吗？

所以，最旧的行 enddate (1/9/19) would change to 1/7/19.

重叠时间可以超过一天。

Lead和/或Lag在这里可以用吗？不知道从哪里开始。

表A

CustDate   id   Name
1/9/19      1   John

表B

StartDate   EndDate      AREA
 1/1/2019    1/9/19      East
 1/8/2019    12/31/4000  Mideast

示例SQL

 ,CASE WHEN ENDDATE >
LEAD(STARTDATE) OVER (PARTITION BY ID ORDER BY STARTDATE) 
THEN MIN(ENDDATE) OVER (PARTITION BY ID) - interval '1' day
ELSE ENDATE
END END_DT2

Answer 1

您可以通过更新 enddate:

来修复 TableB

update tableb b
    set enddate = (select min(startdate) - interval '1' day
                   from tableb b2
                   where b2.startdate > b.startdate
                  );

或者，将其表示为 select:

select b.startdate,
       lead(b.startdate, 1, date '4000-12-31') over (order by b.startdate) - interval '1' day as enddate,
       b.area
from tableb b;

Answer 2

也许 Lead 和 Lag

如下所示：

  ,CASE
   WHEN ENDDATE > LEAD(STARTDATE) OVER (PARTITION BY ID ORDER BY STARTDATE) 
   THEN LEAD (STARTDATE) OVER (PARTITION BY ID ORDER BY STARTDATE) -1
               ELSE ENDDATE
               END END_DT

重叠日期

Overlaping dates

sql

oracle

lag

lead