SELECT a.last_name, a.salary, a.department_id, b.salavg
FROM employees a, ( SELECT
department_id, AVG(salary)
salavg
FROM employees
GROUP BY department_id) b
WHERE a.department_id = b. department_id AND
a.salary >b. salavg
In exemplu se observa ca subinterogarii (de fapt rezultatului
acesteia) i s-a atribuit aliasul b, iar interogarea principala
se refera la coloana salavg utilizand acest alias.