MySQL CROSS JOIN Keyword
SQL CROSS JOIN Keyword
The CROSS JOIN keyword returns the Cartesian
product of two or more
tables (combines every row from the first table with every row from the second
table).
Note: So, if the first table has 100 rows, and the second
table has 500 rows, the result set will be 100x500 rows. Be aware that
CROSS JOIN can potentially return very large
result-sets!
CROSS JOIN Syntax
SELECT column_name(s)
FROM table1
CROSS JOIN table2;Demo Database
In this tutorial we will use the well-known Northwind sample database.
Below is 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 |
And 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 |
MySQL CROSS JOIN Example
The following SQL statement selects all customers, and all orders:
Example
SELECT Customers.CustomerName, Orders.OrderID
FROM Customers
CROSS JOIN Orders;
Try it Yourself »
Note: The CROSS JOIN keyword returns all matching
records from both tables whether the other table matches or not. So, if
there are rows in "Customers" that do not have matches in "Orders", or if there
are rows in "Orders" that do not have matches in "Customers", those rows will be
listed as well.
If you add a WHERE clause (if table1 and
table2 has a relationship), the CROSS JOIN will
produce the same result as the INNER JOIN clause:
Example
SELECT Customers.CustomerName, Orders.OrderID
FROM Customers
CROSS JOIN Orders
WHERE Customers.CustomerID=Orders.CustomerID;
Try it Yourself »
