second highest
SELECT
* FROM employee e1
WHERE
2 = (SELECT COUNT(DISTINCT (e2.Emp_Salary))FROM emp e2 WHERE e2.Emp_Salary >= e1.Emp_Salary)
second lowest
SELECT * FROM employee e1
WHERE
2 = (SELECT COUNT(DISTINCT (e2.Emp_Salary))FROM emp e2 WHERE e2.Emp_Salary <= e1.Emp_Salary)
SELECT salary FROM TN a
WHERE n - 1 = (SELECT COUNT(salary) FROM TN b WHERE b.salary > a.salary)
oracle
..........
select max(sal) from emp where sal not in (select max(sal) from emp)
