Oracle opening and closing balance - SQL or PL/SQL needed? - sql

Question

select year,
month ,
d.PROD_ID,
T.CUSTOMER_ID,
SUM(CASE WHEN D.OP_TYPE = 1 THEN d.qty END) EARNED,
SUM(CASE WHEN D.OP_TYPE = 2 THEN d.qty END) SPEND
FROM TXN_HEADER T ,
TXN_DETAIL d ,
CUSTOMER A,
PRODUCT e
WHERE T.AMOUNT > 0
AND A.TYPE = 0
AND T.CUSTOMER_ID = A.CUSTOMER_ID
AND T.TXN_PK = D.TXN_PK
and d.PROD_ID = e.PROD_ID
and e.unit = 0
group by year, month ,d.PROD_ID, T.CUSTOMER_ID
ORDER BY 1,2,3,4
Output is as follows (here opening and closing not generated by query, but I required that has to be from the query)
YEAR MONTH PROD CUSTOMER OPENING EARNED SPEND CLOSING
---- ----- ---- -------- ------- ------ ----- -------
2012 8 548 12033 0 8 2 6
2012 9 509 12033 0 24 0 24
2012 9 509 12047 0 14 0 14
2012 9 548 12033 6 1 0 7
2012 9 548 12047 0 1 0 1
I required to generate the output as above. Here PROD_ID,CUSTOMER_ID wise dynamically the prev closing balance to be populated as opening and it shoulde calculate closing balance (opening+earned-spend) monthwise,customer wise ,product wise. is it possible to write in SQL or need to go PL/SQL?

Answer 1

I'd use analytics, with PROD_ID and CUSTOMER_ID in the partition clause to avoid mixing products and customers.
WITH
MONTHLY_BALANCE AS
(
SELECT
YEAR,
MONTH,
D.PROD_ID,
T.CUSTOMER_ID,
SUM(CASE WHEN D.OP_TYPE = 1 THEN D.QTY ELSE NULL END) EARNED,
SUM(CASE WHEN D.OP_TYPE = 2 THEN D.QTY ELSE NULL END) SPEND,
FROM TXN_HEADER T
JOIN CUSTOMER A
ON T.CUSTOMER_ID = A.CUSTOMER_ID
JOIN TXN_DETAIL D
ON T.TXN_PK = D.TXN_PK
JOIN PRODUCT E
ON D.PROD_ID = E.PROD_ID
WHERE T.AMOUNT > 0
AND A.TYPE = 0
AND E.UNIT = 0
GROUP BY YEAR, MONTH, D.PROD_ID, T.CUSTOMER_ID
)
SELECT
YEAR,
MONTH,
PROD_ID,
CUSTOMER_ID,
SUM(NVL(EARNED, 0) - NVL(SPEND, 0)) OVER(PARTITION BY PROD_ID, CUSTOMER_ID ORDER BY YEAR, MONTH ROWS BETWEEN UNBOUNDED PRECEDING AND 1 PRECEDING) OPENING,
EARNED,
SPEND,
SUM(NVL(EARNED, 0) - NVL(SPEND, 0)) OVER(PARTITION BY PROD_ID, CUSTOMER_ID ORDER BY YEAR, MONTH ROWS BETWEEN UNBOUNDED PRECEDING AND CURRENT_ROW) CLOSING
FROM MONTHLY_BALANCE
ORDER BY 1, 2, 3, 4

Answer 2

Your CASE needs an ELSE
CASE WHEN D.OP_TYPE = 1 THEN d.qty ELSE 0 END
Without the else the CASE will return NULL when D.OP_TYPE is not equal to 1, and anything+NULL=NULL. When your WHEN is not satisfied it returns NULL and that is why you do not see anything for those columns.
To get OPENING and CLOSING calculated as you may want to use analytic functions like LEAD and LAG.
Select year,month,prod_id,customer_id,
LAG(closing,1,0) OVER (order by year,month,prod_id,customer_id) as opening,
earned,spend
,(LAG(closing,1,0) OVER (order by year,month,prod_id,customer_id)+closing) as closing
from (WITH temp AS (select year,
month ,
d.PROD_ID,
T.CUSTOMER_ID,
0 OPEN,
SUM(CASE WHEN D.OP_TYPE = 1 THEN d.qty END) EARNED,
SUM(CASE WHEN D.OP_TYPE = 2 THEN d.qty END) SPEND,
0 CLOSE
FROM TXN_HEADER T ,
TXN_DETAIL d ,
CUSTOMER A,
PRODUCT e
WHERE T.AMOUNT > 0
AND A.TYPE = 0
AND T.CUSTOMER_ID = A.CUSTOMER_ID
AND T.TXN_PK = D.TXN_PK
and d.PROD_ID = e.PROD_ID
and e.unit = 0
group by year, month ,d.PROD_ID, T.CUSTOMER_ID
ORDER BY 1,2,3,4)
SELECT year,month,prod_id,customer_id,open,earned,spend,(open+earned-spend) as closing
from temp);