java - MySQL SUBTRACT 与 SUM 查询一个单列同一个表

Question

交易表：

+---------+--------+-------------+--------------+-----+
| 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)
+---------+--------+-------------+--------------+-----|

钥匙：

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

有很多产品，但现在只关注一个 SFCode “12”。

QTY 是商店中的 Physical Stock PRESENT，DocType 是交易。

我需要用这张桌子做两件事。

1. 获取当前库存，即 (FP+LP+CSR+CRR) - (FPR+LPR+CAS+CRS)注意：可能没有特定 DocType 的交易

2. 获取特定保修代码尚未售罄的产品的保修代码。在表最后一列（未命名）中从上到下走，你会明白的。

请建议 Java-MySql 语句来帮助我实现这个结果。任何帮助表示赞赏。

Answer 1

为＃1尝试这样的事情：

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);

这是我对 #2 的看法：（假设 SFCode 不是整数）

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;

现在不能自己真正测试这个，但这至少应该给你一个想法。