SQL INNER JOIN Keyword
SQL INNER JOIN Keyword
The INNER JOIN keyword selects records that have matching values in both tables.
INNER JOIN Syntax
SELECT column_name(s)
FROM table1
INNER JOIN table2
ON table1.column_name = table2.column_name;
FROM table1
INNER JOIN table2
ON table1.column_name = table2.column_name;
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Demo Database
In this tutorial we will use the well-known Northwind sample database.
Below is a selection from the "Orders" table:
| OrderID | CustomerID | EmployeeID | OrderDate | ShipperID |
|---|---|---|---|---|
| 10308 | 2 | 7 | 1996-09-18 | 3 |
| 10309 | 37 | 3 | 1996-09-19 | 1 |
| 10310 | 77 | 8 | 1996-09-20 | 2 |
And a selection from the "Customers" table:
| CustomerID | CustomerName | ContactName | Address | City | PostalCode | Country |
|---|---|---|---|---|---|---|
| 1 |
Alfreds Futterkiste | Maria Anders | Obere Str. 57 | Berlin | 12209 | Germany |
| 2 | Ana Trujillo Emparedados y helados | Ana Trujillo | Avda. de la Constitución 2222 | México D.F. | 05021 | Mexico |
| 3 | Antonio Moreno Taquería | Antonio Moreno | Mataderos 2312 | México D.F. | 05023 | Mexico |
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SQL INNER JOIN Example
The following SQL statement selects all orders with customer information:
Example
SELECT Orders.OrderID, Customers.CustomerName
FROM Orders
INNER JOIN Customers ON Orders.CustomerID = Customers.CustomerID;
FROM Orders
INNER JOIN Customers ON Orders.CustomerID = Customers.CustomerID;
Note: 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!
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JOIN Three Tables
The following SQL statement selects all orders with customer and shipper information:
Example
SELECT Orders.OrderID, Customers.CustomerName, Shippers.ShipperName
FROM ((Orders
INNER JOIN Customers ON Orders.CustomerID = Customers.CustomerID)
INNER JOIN Shippers ON Orders.ShipperID = Shippers.ShipperID);
FROM ((Orders
INNER JOIN Customers ON Orders.CustomerID = Customers.CustomerID)
INNER JOIN Shippers ON Orders.ShipperID = Shippers.ShipperID);
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