leetcode.177. Nth Highest Salary

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 INTBEGIN  declare M INT;  SET M = N -1;  RETURN (      # Write your MySQL query statement below.      select distinct Salary from Employee order by Salary desc limit M,1  );END