MySQL - RIGHT OUTER JOIN
The MySQL 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 MySQL 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
EmpID | Name | City | Age | Salary |
---|---|---|---|---|
1 | John | London | 25 | 3000 |
2 | Marry | New York | 24 | 2750 |
3 | Jo | Paris | 27 | 2800 |
4 | Kim | Amsterdam | 30 | 3100 |
5 | Ramesh | New Delhi | 28 | 3000 |
6 | Huang | Beijing | 28 | 2800 |
Table 2: Contact_Info table
Phone_Number | EmpID | Address | Gender |
---|---|---|---|
+1-8054098000 | 2 | Brooklyn, New York, USA | F |
+33-147996101 | 3 | Grenelle, Paris, France | M |
+31-201150319 | 4 | Geuzenveld, Amsterdam, Netherlands | F |
+86-1099732458 | 6 | Yizhuangzhen, Beijing, China | M |
+65-67234824 | 7 | Yishun, Singapore | M |
+81-357799072 | 8 | Koto City, Tokyo, Japan | M |
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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 MySQL 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