The FULL OUTER JOIN
keyword returns all records when there is a match in left (table1) or right (table2) table records.
Tip: FULL OUTER JOIN
and FULL JOIN
are the same.
SELECT
column_name(s)
FROM
table1
FULL OUTER JOIN
table2
ON
table1.column_name =
table2.column_name
WHERE
condition;
Note: FULL OUTER JOIN
can potentially return very large result-sets!
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 |
The following SQL statement selects all customers, and all orders:
SELECT Customers.CustomerName, Orders.OrderID
FROM Customers
FULL OUTER JOIN Orders ON Customers.CustomerID=Orders.CustomerID
ORDER BY Customers.CustomerName;
A selection from the result set may look like this:
CustomerName | OrderID |
---|---|
Null | 10309 |
Null | 10310 |
Alfreds Futterkiste | Null |
Ana Trujillo Emparedados y helados | 10308 |
Antonio Moreno Taquería | Null |
Note: The FULL OUTER 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.
截取页面反馈部分,让我们更快修复内容!也可以直接跳过填写反馈内容!