SQL RIGHT JOIN Keyword
The RIGHT JOIN keyword returns all the rows from the right table (table_name2), even if there are no matches in the left table (table_name1).
SQL RIGHT JOIN Syntax
| SELECT column_name(s) FROM table_name1 RIGHT JOIN table_name2 ON table_name1.column_name=table_name2.column_name |
PS: In some databases RIGHT JOIN is called RIGHT OUTER JOIN.
SQL RIGHT JOIN Example
The "Persons" table:
| P_Id | LastName | FirstName | Address | City |
|---|---|---|---|---|
| 1 | Hansen | Ola | Timoteivn 10 | Sandnes |
| 2 | Svendson | Tove | Borgvn 23 | Sandnes |
| 3 | Pettersen | Kari | Storgt 20 | Stavanger |
The "Orders" table:
| O_Id | OrderNo | P_Id |
|---|---|---|
| 1 | 77895 | 3 |
| 2 | 44678 | 3 |
| 3 | 22456 | 1 |
| 4 | 24562 | 1 |
| 5 | 34764 | 15 |
Now we want to list all the orders with containing persons - if any, from the tables above.
We use the following SELECT statement:
| SELECT Persons.LastName, Persons.FirstName, Orders.OrderNo FROM Persons RIGHT JOIN Orders ON Persons.P_Id=Orders.P_Id ORDER BY Persons.LastName |
The result-set will look like this:
| LastName | FirstName | OrderNo |
|---|---|---|
| Hansen | Ola | 22456 |
| Hansen | Ola | 24562 |
| Pettersen | Kari | 77895 |
| Pettersen | Kari | 44678 |
| 34764 |
The RIGHT JOIN keyword returns all the rows from the right table (Orders), even if there are no matches in the left table (Persons).






0 comments:
Post a Comment