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❮ SQL Keywords
command returns rows that have matching values in both tables. The following SQL selects all orders with customer information:
SELECT Orders.OrderID, Customers.CustomerNameCustomers ON Orders.CustomerID = Customers.CustomerID;The INNER JOIN keyword selects all rows from both tables as long as there is a match between the columns. If there are records in the "Orders" table that do not have matches in "Customers", these orders will not be shown! The following SQL statement selects all orders with customer and shipper information:
SELECT Orders.OrderID, Customers.CustomerName, Shippers.ShipperName((Orders
Formula
INNER JOIN Customers ON Orders.CustomerID = Customers.CustomerID)INNER JOIN Shippers ON Orders.ShipperID = Shippers.ShipperID);command returns all rows from the left table, and the matching rows from the right table. The result is NULL from the right side, if there is no match. The following SQL will select all customers, and any orders they might have:
SELECT Customers.CustomerName, Orders.OrderIDFormula
ON Customers.CustomerID = Orders.CustomerIDORDER BY Customers.CustomerName;keyword returns all records from the left table (Customers), even if there are no matches in the right table (Orders).
command returns all rows from the right table, and the matching records from the left table. The result is NULL from the left side, when there is no match. The following SQL will return all employees, and any orders they might have placed:
SELECT Orders.OrderID, Employees.LastName, Employees.FirstNameFormula
RIGHT JOIN Employees ON Orders.EmployeeID = Employees.EmployeeIDORDER BY Orders.OrderID;keyword returns all records from the right table (Employees), even if there are no matches in the left table (Orders).