PostgreSQL - RIGHT OUTER JOIN

The PostgreSQL RIGHT OUTER JOIN keyword (or sometimes called RIGHT JOIN) is used to combine column values of two tables based on the match between the columns. It returns all rows of the table on the right side of the join and matching rows of the table on the left side of the join. The rows of the right side table where there is no match in the left side table, the result table will contain NULL value.

Syntax

The syntax for using RIGHT OUTER JOIN keyword in PostgreSQL is given below:

SELECT table1.column1, table1.column2, table2.column1, table2.column2, ...
FROM table1
RIGHT OUTER JOIN table2
ON table1.matching_column = table2.matching_column;

Example:

Consider a database containing tables called Employee and Contact_Info with the following records:

Table 1: Employee table

Table 2: Contact_Info table

• To right outer join Employee and Contact_Info tables based on matching column EmpID, the query is given below. This will fetch Name and Age columns from Employee table and Address column from Contact_Info table.

  SELECT Employee.Name, Employee.Age, Contact_Info.Address 
  FROM Employee
  RIGHT OUTER JOIN Contact_Info
  ON Employee.EmpID = Contact_Info.EmpID;
  

  
  

  This will produce the result as shown below:

  Name	Age	Address
  Marry	24	Brooklyn, New York, USA
  Jo	27	Grenelle, Paris, France
  Kim	30	Geuzenveld, Amsterdam, Netherlands
  Huang	28	Yizhuangzhen, Beijing, China
  		Yishun, Singapore
  		Koto City, Tokyo, Japan

• To fetch all fields of a table, table.* keyword is used, for example - to fetch all fields of the Employee table, Employee.* is used in the below PostgreSQL code:

  SELECT Employee.*, Contact_Info.Address 
  FROM Employee
  RIGHT OUTER JOIN Contact_Info
  ON Employee.EmpID = Contact_Info.EmpID;
  

  
  

  This result of the following code will be:

  EmpID	Name	City	Age	Salary	Address
  2	Marry	New York	24	2750	Brooklyn, New York, USA
  3	Jo	Paris	27	2800	Grenelle, Paris, France
  4	Kim	Amsterdam	30	3100	Geuzenveld, Amsterdam, Netherlands
  6	Huang	Beijing	28	2800	Yizhuangzhen, Beijing, China
  					Yishun, Singapore
  					Koto City, Tokyo, Japan