How To Name Query Output Columns?

Each column in the query output has a default name. If you don't like the default name, you can
specify a new name for any column in the query output by using the AS clause. The following
statement shows you a good example:
SQL> SELECT department_id AS ID, MIN(salary) AS Low,
MAX(salary) AS High, AVG(salary) AS Average
FROM employees GROUP BY department_id HAVING AVG(salary) < 5000;
ID LOW HIGH AVERAGE
---------- ---------- ---------- ----------
30 2500 11000 4150
50 2100 8200 3475.55556
10 4400 4400 4400