clear scr

ttitle left "Employee Salary statistics"

SELECT
	(select count(sal) from emp) as "NO of Emp.",
	(select avg(sal) from emp) as "Average",
	(select max(sal) from emp) as "Highest",
	(select min(sal) from emp) as "Lowest",
		(select max(sal) from emp) - (select min(sal) from emp) as "HI/LO"
FROM
	dual;