我在使用 SQL 语句时遇到问题。
基本上我有 5 个表，它们是:
书籍、记录、OrderedBooks、OrderedRecords 和订单。
我的订单包含客户下的所有订单， 我的 orderedRecords 和 orderedBooks 包含与客户订单相关的所有书籍和记录 显然，账簿和记录表包含与每个账簿和记录相关的信息。
My orderedrecords 和 orderedbooks 包含与相应书籍/记录相关的 BookID 和 RecordID。
我正在编写一个应用程序，它需要显示书名、书本成本、书本数量、书本总计(价格*数量)记录标题、记录成本、记录数量、记录总计。
不必使用 SQL 中的数学函数计算帐簿和记录的总数。
到目前为止，我已经设法让它准确地给出我想要的，但是，假设我有 3 个图书订单和 1 个记录订单，对于记录订单的剩余两行，它将复制数据只是空的。我试过左连接和右连接，但都没有用。
这是我的 SQL 语句...
SELECT Books.Title AS BookTitle
, Books.Cost AS BookCost
, OrderedBooks.Quantity AS BookQuantity
, OrderedBooks.Total AS BooksTotal
, Records.Title AS RecordsTitle
, Records.Cost AS RecordsCost
, OrderedRecords.Quantity AS RecordQuantity
, OrderedRecords.Total AS RecordsTotal
-- Nothing wrong with select part
FROM Orders
INNER JOIN OrderedBooks ON OrderedBooks.OrderID = Orders.ID
FULL OUTER JOIN OrderedRecords ON OrderedRecords.OrderID = Orders.ID
LEFT OUTER JOIN Books ON OrderedBooks.BookID = Books.ID
LEFT OUTER JOIN Records ON OrderedRecords.RecordID = Records.ID
WHERE (Orders.ID = 9)
它返回正确订单号的正确订购书籍和记录，但我似乎无法摆脱重复的行
最佳答案
书籍.id:
SELECT Books.Title AS BookTitle
, Books.Cost AS BookCost
, OrderedBooks.Quantity AS BookQuantity
, OrderedBooks.Total AS BooksTotal
, Records.Title AS RecordsTitle
, Records.Cost AS RecordsCost
, OrderedRecords.Quantity AS RecordQuantity
, OrderedRecords.Total AS RecordsTotal
FROM Orders
INNER JOIN OrderedBooks ON OrderedBooks.OrderID = Orders.ID
FULL OUTER JOIN OrderedRecords ON OrderedRecords.OrderID = Orders.ID
LEFT OUTER JOIN Books ON OrderedBooks.BookID = Books.ID
LEFT OUTER JOIN Records ON OrderedRecords.RecordID = Records.ID
WHERE (Orders.ID = 9)
GROUP BY Books.ID
关于sql - 在 SQL 中连接 5 个表，我们在Stack Overflow上找到一个类似的问题： https://stackoverflow.com/questions/14803135/