MySQL的減法SUM查詢一個單柱相同的表

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 

有很多產品，但現在集中在一個單一SFCode 「12」。

QTY是商店中的實體庫存現金，DocType是交易。

我需要用這張桌子做兩件事。

1. 獲取當前股票是（FP + LP + CSR + CRR） - （FPR + LPR + CAS + CRS）注：有可能沒有一個特定的DocType

2. 獲得保證的交易對於特定保修代碼尚未售罄的產品代碼。在表格最後一列（未命名）中從頂部到底部，然後您就會明白。

請建議Java-MySql語句來幫助我實現這個結果。任何幫助表示讚賞。

Answer 1

嘗試這樣的＃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); 

這是我拍的＃2：（這是假設SFCode不是整數）

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; 

不能真正檢驗這個我自己現在，但這至少應該給你一個想法。