关键字 RIGHT JOIN 返回右表 (table2) 中的所有记录以及左表 (table1) 中的相应记录。
如果没有匹配,结果将为左侧 0 条记录。
SELECT column_name(s)
FROM table1
RIGHT JOIN table2
ON table1.column_name = table2.column_name
在本教程中,我们将使用著名的示例数据库“Northwind”。
以下是表“Orders”(“订单”)中的示例:
ProductID | OrderID | CustomerID | EmployeeID | OrderDate | ShipperID |
---|---|---|---|---|---|
1 | 10248 | 90 | 5 | 1996-07-04 | 3 |
2 | 10249 | 81 | 6 | 1996-07-05 | 1 |
3 | 10250 | 34 | 4 | 1996-07-08 | 2 |
4 | 10251 | 84 | 3 | 1996-07-08 | 1 |
5 | 10252 | 76 | 4 | 1996-07-09 | 2 |
并从表“Employees”(“员工”)中进行选择:
EmployeeID | LastName | FirstName | BirthDate | Photo | Notes |
---|---|---|---|---|---|
1 | Davolio | Nancy | 12/8/1968 | EmpID1.pic | Education includes a BA in psychology from Colorado State University. She also completed (The Art of the Cold Call). Nancy is a member of 'Toastmasters International'. |
2 | Fuller | Andrew | 2/19/1952 | EmpID2.pic | Andrew received his BTS commercial and a Ph.D. in international marketing from the University of Dallas. He is fluent in French and Italian and reads German. He joined the company as a sales representative, was promoted to sales manager and was then named vice president of sales. Andrew is a member of the Sales Management Roundtable, the Seattle Chamber of Commerce, and the Pacific Rim Importers Association. |
3 | Leverling | Janet | 8/30/1963 | EmpID3.pic | Janet has a BS degree in chemistry from Boston College). She has also completed a certificate program in food retailing management. Janet was hired as a sales associate and was promoted to sales representative. |
4 | Peacock | Margaret | 9/19/1958 | EmpID4.pic | Margaret holds a BA in English literature from Concordia College and an MA from the American Institute of Culinary Arts. She was temporarily assigned to the London office before returning to her permanent post in Seattle. |
5 | Buchanan | Steven | 3/4/1955 | EmpID5.pic | Steven Buchanan graduated from St. Andrews University, Scotland, with a BSC degree. Upon joining the company as a sales representative, he spent 6 months in an orientation program at the Seattle office and then returned to his permanent post in London, where he was promoted to sales manager. Mr. Buchanan has completed the courses 'Successful Telemarketing' and 'International Sales Management'. He is fluent in French. |
以下 SQL 语句将返回所有员工以及他们可能下的任何订单:
Run SQLSELECT Orders.OrderID, Employees.LastName, Employees.FirstName
FROM Orders
RIGHT JOIN Employees ON Orders.EmployeeID = Employees.EmployeeID
ORDER BY Orders.OrderID