Query to show stock based on previous transactions - sql

Question

Please I need your help..
for an Objective
match SO (Sales Order) quantity to PO (Purchase Order) quantity based on FIFO (First In, First Out) where the first stock items purchased must be the first items sold.
I have a table Stock which use to track the movement of stock in and out of imaginary stock warehouse. The warehouse is initially empty, and stock then moves into the warehouse as a result of a stock purchase (‘IN’) and stock moves out of the warehouse when it is sold (‘OUT’). Each type of stock item is identified by an ItemID. Each movement of stock in or out of the warehouse, due to a purchase or sale of a given item, results in a row being added to the Stock table, uniquely identified by the value in the StockID identify column, and describing how many items were added or removed and the date of the transaction.
Table stock :
StockId DocumentID ItemID TranDate TranCode Quantity
------------------------------------------------------------
1 PO001 A021 2016.01.01 IN 3
4 SO010 A021 2016.01.02 OUT 2
2 PO002 A021 2016.01.10 IN 7
3 PO003 A021 2016.02.01 IN 9
5 SO011 A021 2016.02.11 OUT 8
6 SO012 A023 2016.02.12 OUT 6
How could I write a query to give output like the table below?
SOID POID Quantity
------------------------
SO010 PO001 2
SO011 PO001 1
SO011 PO002 7
SO012 PO003 6

Answer 1

So, seeing as no one else has given this a go, I figure I'll post something that resembles an answer (I believe).
Essentially, what you want to do is keep track of the number of things you have in stock and the number of things that have gone out, based on the date (I haven't accounted for multiple things coming in or going out on the same date, though).
DECLARE #Table TABLE
(
DocumentID VARCHAR(10) NOT NULL,
TranCode VARCHAR(3) NOT NULL,
TranDate DATE NOT NULL,
Quantity INT NOT NULL
); -- I'm ignoring the other columns here because they don't seem important to your overall needs.
INSERT #Table (DocumentID, TranCode, TranDate, Quantity)
VALUES
('PO001', 'IN', '2016-01-01', 3),
('SO010', 'OUT', '2016-01-02', 2),
('PO002', 'IN', '2016-01-10', 7),
('PO003', 'IN', '2016-02-01', 9),
('SO011', 'OUT', '2016-02-11', 8),
('SO012', 'OUT', '2016-02-12', 6);
WITH CTE AS
(
SELECT DocumentID,
TranCode,
TranDate,
Quantity,
RunningQuantity = -- Determine the current IN/OUT totals.
(
SELECT SUM(Quantity)
FROM #Table
WHERE TranCode = T.TranCode
AND TranDate <= T.TranDate
),
PrevQuantity = -- Keep track of the previous IN/OUT totals.
(
SELECT ISNULL(SUM(Quantity), 0)
FROM #Table
WHERE TranCode = T.TranCode
AND TranDate < T.TranDate
)
FROM #Table T
)
SELECT Outgoing.DocumentID,
Incoming.DocumentID,
Quantity =
CASE WHEN Outgoing.RunningQuantity <= Incoming.RunningQuantity AND Outgoing.PrevQuantity >= Incoming.PrevQuantity
THEN Outgoing.RunningQuantity - Outgoing.PrevQuantity
WHEN Outgoing.RunningQuantity <= Incoming.RunningQuantity AND Outgoing.PrevQuantity < Incoming.PrevQuantity
THEN Outgoing.RunningQuantity - Incoming.PrevQuantity
ELSE Incoming.RunningQuantity - Outgoing.PrevQuantity
END
FROM CTE Outgoing
JOIN CTE Incoming ON
Incoming.TranCode = 'IN'
AND Incoming.RunningQuantity > Outgoing.PrevQuantity
AND Incoming.PrevQuantity < Outgoing.RunningQuantity
WHERE Outgoing.TranCode = 'OUT'
ORDER BY Outgoing.TranDate;
Note: I would highly recommend you keep track of the information in a better way. For example, create a table that actually details which orders took what from which other orders (an order transaction table or something), because while it's not impossible to achieve what you want with the way your data is structured, it's much less complicated if you just store more helpful data.