text: # Time:  O(n^2)
  # Space: O(n)
  #
  # Write a SQL query to get the nth highest salary from the Employee table.
  #
  # +----+--------+
  # | Id | Salary |
  # +----+--------+
  # | 1  | 100    |
  # | 2  | 200    |
  # | 3  | 300    |
  # +----+--------+
  # For example, given the above Employee table, the nth highest salary where n = 2 is 200. If there is no nth highest salary, then the query should return null.
  #
  CREATE FUNCTION getNthHighestSalary(N INT) RETURNS INT
  BEGIN
    RETURN (
       # Write your MySQL query statement below.
       SELECT MAX(Salary) /*This is the outer query part */
              FROM Employee Emp1
              WHERE (N-1) = ( /* Subquery starts here */
                   SELECT COUNT(DISTINCT(Emp2.Salary))
                          FROM Employee Emp2
                          WHERE Emp2.Salary > Emp1.Salary)
    );
  END
  