具有 3 个表引用的 SQL 连接查询答案

【问题标题】：SQL Junction query with 3 table references具有 3 个表引用的 SQL 连接查询
【发布时间】：2015-12-24 01:39:02
【问题描述】：

我希望从我的数据输入中识别出所有从 danmurphys 购买的 2012 年生产的酒瓶。我的查询语法不正确，我不确定自己做错了什么。

您的帮助将不胜感激:)

CREATE TABLE Retailer
(RETAIL_ID NVARCHAR(4) NOT NULL,
RETAIL_NAME NVARCHAR(30) NOT NULL,
PRIMARY KEY (RETAIL_ID));

CREATE TABLE Wine
(WINE_ID NVARCHAR(3) NOT NULL,
WINE_NAME NVARCHAR(30) NOT NULL,
WINE_VINT NVARCHAR(4) NOT NULL,
PRIMARY KEY(WINE_ID));

CREATE TABLE Dist
(RETAIL_ID NVARCHAR(4) NOT NULL,
WINE_ID NVARCHAR(3) NOT NULL,
WINE_PRICE DECIMAL(6,2) NOT NULL,
CONSTRAINT PK_Dist PRIMARY KEY
    (
        RETAIL_ID,
        WINE_ID
    ),
    FOREIGN KEY (RETAIL_ID) REFERENCES Retailer (RETAIL_ID),
    FOREIGN KEY (WINE_ID) REFERENCES Wine (WINE_ID));


INSERT INTO Wine VALUES('101','Grange','2010');
INSERT INTO Wine VALUES('102','Grange','2006');
INSERT INTO Wine VALUES('103','Reserve Shiraz','2013');
INSERT INTO Wine VALUES('104','Grey Label Shiraz','2012');
INSERT INTO Wine VALUES('105','Patricia Shiraz','2009');
INSERT INTO Wine VALUES('106','Ten Acres Shiraz','2012');
INSERT INTO Wine VALUES('107','Double Barrel Shiraz','2012');
INSERT INTO Wine VALUES('108','Platinum Label Shiraz','2006');

INSERT INTO Retailer VALUES('1001', 'Dan Murphys');
INSERT INTO Retailer VALUES('1002', 'Woolworths');

INSERT INTO Dist VALUES('1001','101','750');
INSERT INTO Dist VALUES('1001','102','700');
INSERT INTO Dist VALUES('1001','103','10');
INSERT INTO Dist VALUES('1001','104','35');
INSERT INTO Dist VALUES('1001','105','50');
INSERT INTO Dist VALUES('1001','106','25');
INSERT INTO Dist VALUES('1001','107','15');
INSERT INTO Dist VALUES('1001','108','170');
INSERT INTO Dist VALUES('1002','103','9');
INSERT INTO Dist VALUES('1002','104','33');
INSERT INTO Dist VALUES('1002','105','44');

SELECT Wine.WINE_NAME, Dist.WINE_PRICE, Retailer.RETAIL_NAME
FROM Wine
INNER JOIN Dist ON (Dist.RETAIL_ID = Retailer.RETAIL_ID)
INNER JOIN Retailer on (Dist.RETAIL_ID = Retailer.RETAIL_ID)
WHERE Retailer.RETAIL_ID = '1001' AND Wine.WINE_VINT = '2012'

【问题讨论】：

为什么要在十进制列中插入字符值？ (WINE_PRICE) 我的 dbms 出现错误，所以我不能简单地剪切和粘贴您的代码...
将第一个内部连接更改为在 wine_id 上加入

标签： mysql sql junction-table junction

【解决方案1】：

改变了 Wine 和 dist 之间的 JOIN 条件：

SELECT Wine.WINE_NAME, Dist.WINE_PRICE, Retailer.RETAIL_NAME
FROM Wine
INNER JOIN Dist ON (Dist.wine_id = wine.WINE_ID)
INNER JOIN Retailer on (Dist.RETAIL_ID = Retailer.RETAIL_ID)
WHERE Retailer.RETAIL_ID = '1001' AND Wine.WINE_VINT = '2012'

结果是：

SQL>SELECT Wine.WINE_NAME, Dist.WINE_PRICE, Retailer.RETAIL_NAME
SQL&FROM Wine
SQL&INNER JOIN Dist ON (Dist.wine_id = wine.WINE_ID)
SQL&INNER JOIN Retailer on (Dist.RETAIL_ID = Retailer.RETAIL_ID)
SQL&WHERE Retailer.RETAIL_ID = '1001' AND Wine.WINE_VINT = '2012';
WINE_NAME                      WINE_PRICE RETAIL_NAME
============================== ========== ==============================
Grey Label Shiraz                   35.00 Dan Murphys
Ten Acres Shiraz                    25.00 Dan Murphys
Double Barrel Shiraz                15.00 Dan Murphys

                  3 rows found

【讨论】：