how to select top 3 salary in last 30 days code example

Example 1: n highest salary in sql

SELECT TOP 1 salary
FROM (
SELECT DISTINCT TOP N salary
FROM #Employee
ORDER BY salary DESC
) AS temp
ORDER BY salary

Example 2: nth highest salary in sql

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;