Question

在下面的查询中，我试图制作一个快速摘要表来显示一些信息。使用where子句意味着从数据库中查找与该发布者相关的信息。在查看了一个小时左右的其他定义之后，我无法看到我出错的地方。

很抱歉这是一个痛苦，这可能是一件非常简单的事情，但我在下面的查询中有任何明显的错误。

    SELECT Publisher.Name AS "Publisher Name", 
       Book.Title AS "Book Title", 
       ShopOrder.OrderDate AS "Order Date", 
       OrderLine.Quantity AS "Order Quantity", 
       (SUM(Quantity*UnitSellingPrice)) AS "Total Value"
   FROM ShopOrder
   INNER JOIN OrderLine
   ON ShopOrder.ShopOrderID=OrderLine.ShopOrderID
   INNER JOIN Book
   ON OrderLine.BookID=Book.BookID
   INNER JOIN Publisher
   ON Publisher.PublisherID=Book.PublisherID
   WHERE Publisher.Name='Oxford'
   GROUP BY ShopOrder.ShopOrderID, 
            Publisher.PublisherID, 
            Book.BookID, 
            OrderLine.Quantity
   ORDER BY ShopOrder.OrderDate;

非常感谢任何可以提供帮助的人！

编辑：相关表格定义

CREATE TABLE Publisher
(
    PublisherID INTEGER,
    Name VARCHAR(50),

    PRIMARY KEY(PublisherID)
);

CREATE TABLE Book
(
    BookID INTEGER,
    Title VARCHAR(50),
    Price DECIMAL (10, 2),
    CategoryID INTEGER REFERENCES Category(CategoryID),
    PublisherID INTEGER REFERENCES Publisher(PublisherID),

    PRIMARY KEY(BookID)

);

CREATE TABLE ShopOrder
(
    ShopOrderID INTEGER,
    OrderDate DATE,
    ShopID INTEGER REFERENCES Shop(ShopID),
    SalesRepID INTEGER REFERENCES SalesRep(SalesRepID),

    PRIMARY KEY(ShopOrderID)
);

CREATE TABLE OrderLine
(
    ShopOrderID INTEGER REFERENCES ShopOrder(ShopOrderID) ON DELETE CASCADE,
    BookID INTEGER REFERENCES Book(BookID),
    Quantity INTEGER,
    UnitSellingPrice DECIMAL (10,2)
);

Answer 1

这不是一个明确的答案，但我已添加它以显示 I 将如何调试查询：

从Publisher开始：

SELECT Publisher.Name AS "Publisher Name"
FROM Publisher
WHERE Publisher.Name='Oxford'

检查结果......

添加Book

SELECT Publisher.Name AS "Publisher Name", 
   Book.Title AS "Book Title"
FROM Book
INNER JOIN Publisher
ON Publisher.PublisherID=Book.PublisherID
WHERE Publisher.Name='Oxford'

检查结果......

添加OrderLine：

SELECT Publisher.Name AS "Publisher Name", 
   Book.Title AS "Book Title", 
   OrderLine.Quantity AS "Order Quantity"
FROM  OrderLine
INNER JOIN Book
  ON OrderLine.BookID=Book.BookID
INNER JOIN Publisher
  ON Publisher.PublisherID=Book.PublisherID
WHERE Publisher.Name='Oxford'

检查结果......

添加ShopOrder

SELECT Publisher.Name AS "Publisher Name", 
   Book.Title AS "Book Title", 
   ShopOrder.OrderDate AS "Order Date", 
   OrderLine.Quantity AS "Order Quantity"
FROM  ShopOrder
INNER JOIN OrderLine
  ON ShopOrder.ShopOrderID=OrderLine.ShopOrderID
INNER JOIN Book
  ON OrderLine.BookID=Book.BookID
INNER JOIN Publisher
  ON Publisher.PublisherID=Book.PublisherID
WHERE Publisher.Name='Oxford'

检查结果......

添加SUM和GROUPING：

 SELECT Publisher.Name AS "Publisher Name", 
   Book.Title AS "Book Title", 
   ShopOrder.OrderDate AS "Order Date", 
   OrderLine.Quantity AS "Order Quantity", 
   (SUM(Quantity*UnitSellingPrice)) AS "Total Value"
FROM  ShopOrder
INNER JOIN OrderLine
  ON ShopOrder.ShopOrderID=OrderLine.ShopOrderID
INNER JOIN Book
  ON OrderLine.BookID=Book.BookID
INNER JOIN Publisher
  ON Publisher.PublisherID=Book.PublisherID
WHERE Publisher.Name='Oxford'
GROUP BY ShopOrder.ShopOrderID, 
         Publisher.PublisherID, 
         Book.BookID, 
         OrderLine.Quantity
ORDER BY ShopOrder.OrderDate;

Answer 2

Stanleys的回答是在这种情况下真正有用的，但对于任何人来说，在某种程度上寻找答案，正确的查询应如下所示。

SELECT Publisher.Name AS "Publisher Name", Book.Title AS "Book Title", ShopOrder.OrderDate AS "Order Date", 
OrderLine.Quantity AS "Order Quantity", (SUM(Quantity*UnitSellingPrice)) AS "Total Value"
FROM ShopOrder
INNER JOIN OrderLine
ON ShopOrder.ShopOrderID=OrderLine.ShopOrderID
INNER JOIN Book
ON OrderLine.BookID=Book.BookID
INNER JOIN Publisher
ON Publisher.PublisherID=Book.BookID
WHERE Publisher.Name='Oxford'
GROUP BY publisher.name, book.title, shoporder.orderdate, orderline.quantity
ORDER BY ShopOrder.OrderDate;

SQL where子句什么都不返回

2 个答案: