LEFT JOIN is an SQL operator used to retrieve all records from the left table and only match records from the right table.
If no match is found in the right table, then it returns NULL for the right table’s columns. In this process, the columns act as operands.
Syntax:
SELECT columns FROM table1 LEFT JOIN table2 ON table1.common_column = table2.common_column;
Example:
Table1: Employee Employee_id name Department_id 1 Mohan 11 2 Anaya 12 3 Babita 13 Table2: Department Department_id Department_name 11 HR 12 IT 14 Finance
SQL Query:
SELECT Employee.name, Department.department_name FROM Employee LEFT JOIN Department ON Employee.department_id = Department.department_id;
Output:
Name Department_name Mohan HR Anaya IT Babita NULL