SQL: How to split data from quaterly to monthly with date - sql

Question

I have the data in the sql table in quarterly format. I need to be able to split it into monthly with value split evenly ([value/3) in to each month. Can you please assist on how to achieve this using SQL? Thank you.
start
end
value
2022-01-01
2022-04-01
25629
2022-04-01
2022-07-01
993621
CREATE TABLE #your_tbl
("start_dt" timestamp, "end_dt" timestamp, "values" int)
;
INSERT INTO #your_tbl
("start_dt", "end_dt", "values")
VALUES
('2020-01-01 00:00:00', '2020-04-01 00:00:00', 114625),
('2020-04-01 00:00:00', '2020-07-01 00:00:00', 45216),
('2020-07-01 00:00:00', '2020-10-01 00:00:00', 513574)
DECLARE #datefrom datetime
DECLARE #dateto datetime
SET #datefrom='2022-04-01'
SET #dateto = '2022-07-01'
;WITH cte AS
(
SELECT #datefrom as MyDate
UNION ALL
SELECT DATEADD(month,1,MyDate)
FROM cte
WHERE DATEADD(month,1,MyDate)<#dateto
),
combined AS (
SELECT *
FROM #your_tbl q
JOIN cte m
ON YEAR(m.MyDate) >= q.start_dt
AND MONTH(m.MyDate) < q.end_dt
)
SELECT *, [values]/COUNT(1) OVER(PARTITION BY [start_dt], [end_dt]) as monthly_values
FROM combined
DROP TABLE #your_tbl

Answer 1

In Oracle can you use this script:
with mytable as (
select to_date('2022-01-01', 'YYYY-MM-DD') as startX, to_date('2022-04-01', 'YYYY-MM-DD') as endX, 25629 as valueX from dual union
select to_date('2022-04-01', 'YYYY-MM-DD') as startX, to_date('2022-07-01', 'YYYY-MM-DD') as endX, 993621 as valueX from dual union
select to_date('2022-07-01', 'YYYY-MM-DD') as startX, to_date('2022-10-01', 'YYYY-MM-DD') as endX, 21 as valueX from dual union
select to_date('2022-10-01', 'YYYY-MM-DD') as startX, to_date('2023-01-01', 'YYYY-MM-DD') as endX, 7777 as valueX from dual
),
mymonths as (
select '01' as month_n from dual union
select '02' as month_n from dual union
select '03' as month_n from dual union
select '04' as month_n from dual union
select '05' as month_n from dual union
select '06' as month_n from dual union
select '07' as month_n from dual union
select '08' as month_n from dual union
select '09' as month_n from dual union
select '10' as month_n from dual union
select '11' as month_n from dual union
select '12' as month_n from dual
)
select month_n, startX, valueX/3
from mytable, mymonths
where month_n between to_char(startX, 'MM') and to_char(endX-1, 'MM');
MONTHS_N STARTX VALUEX/3
-------- ---------- ----------
01 01/01/2022 8543
02 01/01/2022 8543
03 01/01/2022 8543
04 01/04/2022 331207
05 01/04/2022 331207
06 01/04/2022 331207
07 01/07/2022 7
08 01/07/2022 7
09 01/07/2022 7
10 01/10/2022 2592,33333
11 01/10/2022 2592,33333
12 01/10/2022 2592,33333
Thank you.

Answer 2

Assuming you can figure out how to generate monthly dates, which is RDBMS dependent, here's a solution that might work depending on if you can use window functions.
Note this doesn't hard-code divide by 3 in case you're in a partial quarter.
WITH combined AS (
SELECT *,
FROM your_tbl q
JOIN monthly_dates m
ON m.monthly_dt >= q.start_dt
AND m.monthly_dt < q.end_dt
)
SELECT *
, values / COUNT(1) OVER(PARTITION BY start_dt, end_dt) as monthly_values
FROM combined
sqlfiddle