MySQL SUBTRACT，使用SUM查询同一列的单表

Question

Transactions_Table:

+---------+--------+-------------+--------------+-----+
| DocType | SFCode | Productname | WarrantyCode | QTY |
+---------+--------+-------------+--------------+-----+
|   FP    | 12     | Item        |    1111-01   | 100 | -100
|   FP    | 12     | Item        |    2222-22   | 200 | 
|   FP    | 12     | Item        |    3333-33   | 350 | -350

|   LP    | 12     | Item        |    4444-44   | 10  |
|   LP    | 12     | Item        |    5555-55   | 20  |
|   LP    | 12     | Item        |    6666-66   | 35  | -35

|   CAS   | 12     | Item        |    1111-01   | 50  | -(50 Left, show)
|   CRS   | 12     | Item        |    3333-33   | 120 | -(230 Left, show)
|   CRS   | 12     | Item        |    6666-66   | 35  | -(0 Left, no show)

|   FPR   | 12     | Item        |    1111-01   | 10  | -(40 Left, show)
|   LPR   | 12     | Item        |    5555-55   | 20  | -(0 Left, no show)
|   CSR   | 12     | Item        |    1111-01   | 5   | -(50+5 Left, show)
|   CRR   | 12     | Item        |    6666-66   | 5   | -(Got back 5, show)
+---------+--------+-------------+--------------+-----|

KEY:

FP: Foreign Purchase
LP: Local Purchase

CAS: Cash Sale
CRS: Credit Sale

FPR: Foreign Purchase Return
LPR: Local Purchase Return

CSR: Cash Sale Return
CRR: Credit Sale Return

There are many products but for now focussing on a single SFCode "12".

QTY is the Physical Stock PRESENT in the store, and the DocType are the transactions.

There are 2 Things I need to do with this table.

1. Get Current Stock which is (FP+LP+CSR+CRR) - (FPR+LPR+CAS+CRS) Note: There maybe no transaction of a particular DocType

2. Get Warranty Code(s) for a Product which has not been Sold Out for a particular Warranty Code. Go from Top to Bottom in Table last Column (not named) and you will get the idea.

Please suggest Java-MySql statement(s) that will help me achieve this result. Any help is appreciated.

Answer 1

Try something like this for #1:

SELECT SFCode, SUM(FP+LP+CSR+CRR-FPR-LPR-CAS-CRS) AS Total FROM
(SELECT SFCode,
SUM(IF(DocType = "FP", QTY, 0)) AS FP,
>>please fill out all the columns<<    
FROM Transactions_Table
WHERE SFCode = "12"
GROUP BY DocType);

This is my shot at #2: (This assumes SFCode isn't an integer)

SELECT a.SFCode, a.WarrantyCode, (a.QTY-b.QTY) AS Stock FROM
(SELECT SFCode, WarrantyCode, QTY
FROM Transactions_Table
WHERE SFCode = "12"
AND DocType IN ('FP','LP','CSR','CRR')
GROUP BY WarrantyCode) AS a 
LEFT JOIN
(SELECT SFCode, WarrantyCode, QTY
FROM Transactions_Table
WHERE SFCode = "12"
AND DocType IN ('FPR','LPR','CAS','CRS')
GROUP BY WarrantyCode) AS b
ON a.SFCode = b.SFCode AND a.WarrantyCode = b.WarrantyCode;

Can't really test this myself right now but this should at least give you an idea.