Функції SQL

SQL RIGHT JOIN

SQL RIGHT JOIN Опис

Ключове слово RIGHT JOIN повертає всі записи з правої таблиці (table2) і відповідні записи з лівої таблиці (table1).

Результатом буде 0 записів зліва, якщо немає відповідності.

RIGHT JOIN Синтаксис

SELECT column_name(s)
FROM table1
RIGHT JOIN table2
ON table1.column_name = table2.column_name

У деяких базах даних RIGHT JOIN викликається як RIGHT OUTER JOIN.

SQL INNER JOIN

Демонстраційна база даних

У цьому довіднику ми будемо використовувати відомий приклад бази даних "Northwind".

Нижче наведено вибірку з таблиці "Orders" ("Замовлення"):

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

Та вибірку із таблиці "Employees" ("Працівники"):

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.

SQL RIGHT JOIN Приклад

Наступна SQL-інструкція поверне всіх співробітників і будь-які замовлення, які вони могли розмістити:

Run SQLSELECT Orders.OrderID, Employees.LastName, Employees.FirstName 
FROM Orders 
RIGHT JOIN Employees ON Orders.EmployeeID = Employees.EmployeeID 
ORDER BY Orders.OrderID

Ключове слово RIGHT JOIN повертає всі записи з правої таблиці (Співробітники), навіть якщо немає збігів у лівій таблиці (Замовлення).