The SELF JOIN is used to join the table to itself that why it is known as SELF JOIN.

Syntax:

SELECT <em>columnList </em>FROM <em>table1 t1, table1 t2 </em>WHERE t<em>1.commonColumn </em>= <em>t2. commonColumn</em>;

Example:

SELECT emp1.EMP_NAME FROM EMPLOYEE emp1, EMPLOYEE emp2 
WHERE emp1.AGE = emp2.AGE;

Output:

EMP_NAME
Parmender
Nidhi
Parmender
Parbhjot
Parmender
Nidhi
Parmender
Parbhjot
Parmender
Nidhi