SQL Left Outer Join with Example

The LEFT JOIN keyword returns all records from the left table (table1), and the matching records from the right table (table2).

In a SQL Left Outer Join, we get following rows in our output. It gives the output of the matching row between both the tables. If no records match from the left table, it also shows those records with NULL values.

Syntax:

SELECT column_name(s)
FROM table1
LEFT OUTER JOIN table2
ON table1.column_name = table2.column_name;

Example:

Lets take below two tables

Employee

EmpName	DeptID
Rafferty	31
Jones	33
Heisenberg	33
Robinson	34
Smith	34
Williams	null

Department

DeptID	DepName
31	Sales
33	Engineering
34	Clerical
35	Marketing

SQL Query:

SELECT e.EmpName, d.DepName  
    FROM Employees AS e   
        LEFT OUTER JOIN  Department AS d ON e.DepID == d.DepID; 

Output:

EmpName	DepName
Rafferty	Sales
Jones	Engineering
Heisenberg	Engineering
Robinson	Clerical
Smith	Clerical
Williams	null

Please visit related article below:

• INNER JOIN
• LEFT OUTER JOIN: 
• RIGHT OUTER JOIN: 
• FULL OUTER JOIN: 
• Self Join
• CROSS JOIN