The join condition in the WHERE clause may use operators other than the equal sign (=). For example, to find all employees that are not (!=) managers, the following query can be used:
SELECT lname, fname
FROM dept, employee
WHERE employee.e_no != dept.mgr
AND employee.dept = dept.dept
The query result appears below:
| lname | fname |
|---|---|
| Hurwood | Roger |
| Gross | Mary |
| Wilson | Arthur |
| Chung | Yung |
| Cox | John |
| Crisp | Keith |
| Hurwood | Susan |
| Haley | Olaf |