LeetCode: 177. Nth Highest Salary

题目描述

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 | +------------------------+

解题思路

将员工表按照薪水从高到低排序，取第 n 行数据。

AC 代码

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