second highest from sql code example

Example 1: sql select second max

Both options you find max as a subset and then exclude from main select
sql> SELECT MAX( col ) FROM table
 	WHERE col < ( SELECT MAX( col ) FROM table);
sql> SELECT MAX(col) FROM table 
WHERE col NOT IN (SELECT MAX(col) FROM table);

Example 2: second highest salary in sql

SELECT MAX(SALARY) 'SECOND_MAX' FROM EMPLOYEES
WHERE SALARY <> (SELECT MAX(SALARY) FROM EMPLOYEES);


OR

Here is the solution for nth highest
salary from employees table 

SELECT FIRST_NAME , SALARY FROM 
(SELECT FIRST_NAME, SALARY, DENSE_RANK() OVER
(ORDER BY SALARY DESC) AS SALARY_RANK
FROM EMPLOYEES)
WHERE SALARY_RANK = n;