Saturday, June 18, 2011

SQL RIGHT JOIN Keyword

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_IdLastNameFirstNameAddressCity
1HansenOlaTimoteivn 10Sandnes
2SvendsonToveBorgvn 23Sandnes
3PettersenKariStorgt 20Stavanger
The "Orders" table:
O_IdOrderNoP_Id
1778953
2446783
3224561
4245621
53476415
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:
LastNameFirstNameOrderNo
HansenOla22456
HansenOla24562
PettersenKari77895
PettersenKari44678
  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).

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