Self Join:-
| Employee table | |
|---|---|
| employee_name | employee_location |
| Joe | New York |
| Sunil | India |
| Alex | Russia |
| Albert | Canada |
| Jack | New York |
| NULL | NULL |
SELECT e1.employee_name
FROM employee e1, employee e2
WHERE e1.employee_location = e2.employee_location
AND e2.employee_name="Joe";