Separating Overlapping Date Ranges in Oracle - oracle

Question

I have data with overlapping data ranges. Example below
Customer_ID
FAC_NUM
Start_Date
End_Date
New_Monies
12345
ABC1234
26/NOV/2014
26/MAY/2015
100000
12345
ABC1234
12/DEC/2014
12/JUN/2015
200000
12345
ABC1234
15/JUN/2015
15/DEC/2015
500000
12345
ABC1234
20/DEC/2015
20/JUN/2016
600000
I want to convert this table into data with non overlapping ranges such that for each overlapping period, the New_Monies column is summed together and shown as a new row. For the example above, I want the output to be as follows
Customer_ID
FAC_NUM
Start_Date
End_Date
New_Monies
12345
ABC1234
26/NOV/2014
11/DEC/2014
100000
12345
ABC1234
12/DEC/2014
26/MAY/2015
300000
12345
ABC1234
27/MAY/2015
12/JUN/2015
200000
12345
ABC1234
15/JUN/2015
15/DEC/2015
500000
12345
ABC1234
20/DEC/2015
20/JUN/2016
600000
Row 2 above being the overlapping period of 12 Dec 2014 to 26 May 2015 showing the total New_Monies as 300000 (100000+200000)
What would be the best way to do this in Oracle?
Thanks in advance for your support.
Regards,
Ani

Answer 1

with
prep (customer_id, fac_num, dt, amount) as (
select t.customer_id, t.fac_num,
case h.col when 's' then t.start_date else t.end_date + 1 end as dt,
case h.col when 's' then t.new_monies else - t.new_monies end as amount
from sample_data t
cross join
(select 's' as col from dual union all select 'e' from dual) h
)
, cumul_sums (customer_id, fac_num, dt, amount) as (
select distinct
customer_id, fac_num, dt,
sum(amount) over (partition by customer_id, fac_num order by dt)
from prep
)
, with_intervals (customer_id, fac_num, start_date, end_date, amount) as (
select customer_id, fac_num, dt,
lead(dt) over (partition by customer_id, fac_num order by dt) - 1,
amount
from cumul_sums
)
select customer_id, fac_num, start_date, end_date, amount
from with_intervals
where end_date is not null
order by customer_id, fac_num, start_date
;
The prep subquery unpivots the inputs, while at the same time changing the "end date" to the "start date" of the following interval and assigning a positive amount to the "start date" and the negative of the same amount to the following "start date". cumul_sums computes the cumulative sums; note that if two or more intervals begin on the same date (so the same date from prep appears multiple times for a customer and fac_num), the analytic sum will include the amounts from ALL the rows up to that date - the default windowing clause is range between...... After the cumulative sums are computed, this subquery also de-duplicates the output rows (to handle precisely that complication, of multiple intervals starting on the same date). with_intervals recovers the "start date" - "end date" intervals, and the final step simply removes the last interval ("to infinity") which would have an "amount" of zero.
EDIT This solution answers the OP's original question. After posting the solution, the OP changed the question. The solution can be changed easily to address the new formulation. I'm not going to chase shadows though; the solution will remain as is.

Answer 2

Here is an way to do this.
with all_data
as (select Customer_ID,FAC_NUM,start_date as dt,new_monies as calc_monies
from t
union all
select Customer_ID,FAC_NUM,end_date as dt,new_monies*-1 as calc_monies
from t
)
select x.customer_id
,x.fac_num
,x.start_date
,case when row_number() over(order by end_date desc)=1 then
x.end_date + 1
else x.end_date
end as new_end_date
from (
select t.customer_id
,t.fac_num
,t.dt as start_date
,lead(dt) over(order by dt)-1 as end_date
,sum(calc_monies) over(order by dt) as new_monies
from all_data t
)x
where end_date is not null
order by 3
db fiddle link
https://dbfiddle.uk/?rdbms=oracle_11.2&fiddle=856c9ac0954e45429994f4ac45699e6f
+-------------+---------+------------+--------------+------------+
| CUSTOMER_ID | FAC_NUM | START_DATE | NEW_END_DATE | NEW_MONIES |
+-------------+---------+------------+--------------+------------+
| 12345 | ABC1234 | 26-NOV-14 | 11-DEC-14 | 100000 |
| 12345 | ABC1234 | 12-DEC-14 | 25-MAY-15 | 300000 |
| 12345 | ABC1234 | 26-MAY-15 | 12-JUN-15 | 200000 |
+-------------+---------+------------+--------------+------------+