覆盖日期范围的 SQL 查询

Question

Oracle 11i - 寻找一个查询，该查询将创建一组日期范围，让 CUSTOM 值覆盖 STANDARD 值，并将 STANDARD 值保留在未被覆盖的位置。

STANDARD
CUSTOMER_ID  START_DATE  END_DATE     VALUE
0001         02/01/2013  09/15/2013   10

CUSTOM
CUSTOMER_ID  START_DATE  END_DATE     VALUE
0001         01/15/2013  03/15/2013   20
0001         07/01/2013  07/31/2013   30

Desired Result
CUSTOMER_ID  START_DATE  END_DATE     VALUE
0001         02/01/2103  03/15/2013   20
0001         03/16/2013  06/30/2013   10
0001         07/01/2013  07/31/2013   30
0001         08/01/2013  09/15/2013   10

以下是试运行的结果：

select sc.customer_id, sc.thedate as start_date,
       lead(**sc.thedate**) over (partition by sc.customer_id order by sc.thedate) as end_date,
       sc.value
from (select customer_id, start_date as thedate, value
      from standard
      union all
      select customer_id, start_date, value
      from custom
      union all
      select s.customer_id, c.end_date + 1, s.value
      from custom c join
           standard s
           on c.customer_id = s.customer_id
      union all
      select customer_id, end_date, NULL
      from standard
     ) sc
where value is not NULL;

CUSTOMER_ID     START_DATE              END_DATE                VALUE
0001            15-JAN-13 12.00.00 AM   01-FEB-13 12.00.00 AM   20
0001            01-FEB-13 12.00.00 AM   16-MAR-13 12.00.00 AM   10
0001            16-MAR-13 12.00.00 AM   01-JUL-13 12.00.00 AM   10
0001            01-JUL-13 12.00.00 AM   01-AUG-13 12.00.00 AM   30
0001            01-AUG-13 12.00.00 AM                           10

Answer 1

这是一种方法。将数据分解为值开始的每个日期（针对每个客户）。然后使用 Oracle 分析函数将数据整合在一起。日期是“值”的开始。然后使用lead() 获取下一个日期。

select sc.customer_id, sc.thedate as start_date,
       lead(sc.start_date) over (partition by sc.customer_id order by sc.thedate) as end_date,
       sc.value
from (select s.customer_id, s.start_date as thedate, s.value
      from standard
      union all
      select c.customer_id, c.start_date, c.value
      from custom
      union all
      select s.customer_id, c.end_date + 1, s.value
      from custom c join
           standard s
           on c.customer_id = s.customer_id
      union all
      select s.customer_id, s.end_date, NULL
      from standard
     ) sc
where value is not NULL;

请注意，这包括end_date 的额外记录，您不需要将其作为最后一行。这是用 NULL 值标记的，该值在外部查询中被过滤掉。