如何使用Informatica / SQL在两个记录之间的重叠期间创建新记录

Question

对于以下源数据，需要为重叠期间创建一个新记录，并且其数量应为重叠记录数量的总和。 现有记录的开始日期和结束日期也需要更改，以使它们不会重叠。

资源 ：

ID  StartDate EndDate   Amount
1   1-Jan     31-Jul    100
1   1-Jun     31-Dec    100

预期产量：

ID  StartDate EndDate   Amount
1   1-Jan     31-May    100
1   1-Jun     31-Jul    200
1   1-Aug     31-Dec    100

如何使用SQL（IBM DB2）/ Informatica或两者结合使用？

注意：不能使用存储的proc。

Answer 1

开始的地方是拆分数据，因此只有一列带有数量。 我认为这会产生您想要的：

select id, dte as StartDate,
       lead(dte) over (partition by id, dte) - 1 day as NextDate,
       sum(sum(amount)) over (partition by id order by dte) as amount
from ((select id, startdate as dte, amount
       from t
      ) union all
      (select id, enddate + 1 day, - amount
       from t
      )
     ) t
group by id, dte;

Answer 2

OLAP函数对将一行与下一行进行比较确实很有帮助。 必须创建一个UNION才能创建其他行。 下面的示例分别处理每种类型的行。

-- normal rows without overlapping
select id, startdate, enddate, amount
  from ( select id, startdate, enddate, amount ,
                lead(startdate) over (partition by id order by startdate) as nextstart
           from t )
 where nextstart > enddate

 union all

-- overlapping time ranges

-- first intervall 
select id, startdate, nextstart - 1 day as enddate, amount
  from ( select id, startdate, enddate, amount ,
                lead(startdate) over (partition by id order by startdate) as nextstart
           from t )
 where nextstart < enddate

union all

-- new middle interval
select id, nextstart as startdate,  enddate, amount + nextamount
  from ( select id, startdate, enddate, amount ,
                lead(startdate) over (partition by id order by startdate) as nextstart,
                lead(amount) over (partition by id order by startdate) as nextamount
          from t )
  where nextstart < enddate

union all

-- last interval
select id, prevend + 1 day as startdate,  enddate, amount 
  from ( select id, startdate, enddate, amount ,
                lag(enddate) over (partition by id order by startdate) as prevend
           from t )
 where startdate < prevend