177-sql.md

177. Nth Highest Salary

难度: Medium

刷题内容

原题连接

• https://leetcode.com/problems/nth-highest-salary/

内容描述

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

解题方案

思路 1

CREATE FUNCTION getNthHighestSalary(N INT) RETURNS INT
BEGIN
  RETURN (
      # Write your MySQL query statement below.
      select IFNULL (
          ( select Salary from Employee
            group by Salary
            order by Salary desc 
            limit m, 1), null) 
      as getNthHighestSalary
  );
END

思路2

CREATE FUNCTION getNthHighestSalary(N INT) RETURNS INT
BEGIN
  RETURN (
      # Write your MySQL query statement below.
      select IFNULL (
          ( select DISTINCT Salary from Employee
            order by Salary desc 
            limit m, 1), null) 
      as getNthHighestSalary
  );
END

思路3

CREATE FUNCTION getNthHighestSalary(N INT) RETURNS INT
BEGIN
  RETURN (
      # Write your MySQL query statement below.
      select IFNULL (
          ( select Salary from Employee
            group by Salary
            order by Salary desc 
            limit m, 1), null) 
      as getNthHighestSalary
  );
END