表结构:
Field Type Null Default
--------------------------------------------------------------------
OrderId bigint(20) Yes II is a Primary key
CustomerID bigint(20) Yes
OrderDate date Yes
ShippedDate date Yes NULL
Freight int(20) Yes NULL
ShipName varchar(50) Yes NULL
ShipAddress varchar(100) Yes NULL
ShipCity varchar(50) Yes NULL
ShipPostalCode int(20) Yes NULL
ShipCountry varchar(30) Yes NULL
ShipVia int(50) Yes 1
customerPayA int(11) Yes
discount int(11) Yes
shippingPackagingCost int(11) Yes
grandTotal int(11) Yes NULL
remainPayment int(20) Yes NULL
Table structure for table orderdetails
Field Type Null Default
ProductId int(20) Yes
OrderId int(20) Yes
UnitPrice int(200) Yes
Qty int(20) Yes
vat int(11) Yes
Amount int(20) Yes
Table structure for table products
Field Type Null Default
ProductId int(20) Yes
ProductName varchar(50) Yes
Table structure for table shippers
Field Type Null Default
ShipperID int(11) Yes
companyName varchar(30) Yes
Table structure for table customers
Field Type Null Default
CustomerID int(20) Yes
firstName varchar(20) Yes
middleName varchar(20) Yes
LastName varchar(20) Yes
address varchar(200) Yes
city varchar(20) Yes
postalcode int(10) Yes
country varchar(20) Yes
选择查询:
SELECT DISTINCT
o.OrderID, o.CustomerID,
c.firstName as BillName ,
s.CompanyName as ShipperName,
p.ProductName, od.UnitPrice, od.Qty, od.Amount,
o.grandTotal
FROM
Orders o
JOIN
Customers c ON o.CustomerID = c.CustomerID
JOIN
Shippers s ON o.ShipVia = s.ShipperID
JOIN
OrderDetails od ON o.OrderID = od.OrderID
JOIN
Products p ON od.ProductID = p.ProductID
WHERE
o.OrderID =46
- orderid下的订单表为主键
- customerid下的customer表为主键
- shipperid下的shippers表为主键
[![sql select query下的图片带输出,便于理解][1]][1]
输出看起来像这样:
OrderID CustomerID BillName Shipper Product UnitPrice Qty Amount grandTotal
46 1 bharat balaji evergreent 400 4 1600 3885
46 1 bharat balaji evergreent 400 4 1600 3885
46 1 bharat balaji corogen 700 3 2100 3885
46 1 bharat balaji corogen 700 3 2100 3885
最佳答案
你写的查询没问题,你已经使用了 Distinct 所以它不应该返回重复的记录。
请检查您的表的原始数据。
应该有重复的数据,但有细微的变化,比如空格或不可见字符......
关于java - 为什么这些连接查询返回重复记录?,我们在Stack Overflow上找到一个类似的问题: https://stackoverflow.com/questions/33591270/