177. Nth Highest Salary

CREATE FUNCTION getNthHighestSalary(N INT) RETURNS INT
BEGIN
    # Write your MySQL query statement below.
    DECLARE X INT;
    SET X = N-1;
    RETURN (
        SELECT
            DISTINCT Salary AS getNthHighestSalary
        FROM 
            Employee
        GROUP BY
            Salary
        ORDER BY
            Salary DESC LIMIT X, 1
    );
END