Leetcode177. 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.

+————————+
| getNthHighestSalary(2) |
+————————+
| 200 |
+————————+

和上一题没什么差别，输出第2个和第n个是一样的。

CREATE FUNCTION getNthHighestSalary(N INT) RETURNS INTBEGINDECLARE M INT;SET M=N-1;  RETURN (      # Write your MySQL query statement below.      SELECT IFNULL(     (SELECT DISTINCT Salary FROM Employee      ORDER BY Salary DESC LIMIT M,1) ,    NULL)  );END