Question

177. Nth Highest Salary

中文文档

Description

Table: Employee

+-------------+------+
| Column Name | Type |
+-------------+------+
| id      | int  |
| salary    | int  |
+-------------+------+
id is the primary key (column with unique values) for this table.
Each row of this table contains information about the salary of an employee.

 

Write a solution to find the nth highest salary from the Employee table. If there is no nth highest salary, return null.

The result format is in the following example.

 

Example 1:

Input: 
Employee table:
+----+--------+
| id | salary |
+----+--------+
| 1  | 100  |
| 2  | 200  |
| 3  | 300  |
+----+--------+
n = 2
Output: 
+------------------------+
| getNthHighestSalary(2) |
+------------------------+
| 200          |
+------------------------+

Example 2:

Input: 
Employee table:
+----+--------+
| id | salary |
+----+--------+
| 1  | 100  |
+----+--------+
n = 2
Output: 
+------------------------+
| getNthHighestSalary(2) |
+------------------------+
| null           |
+------------------------+

Solutions

Solution 1

import pandas as pd


def nth_highest_salary(employee: pd.DataFrame, N: int) -> pd.DataFrame:
  unique_salaries = employee.salary.unique()
  if len(unique_salaries) < N:
    return pd.DataFrame([np.NaN], columns=[f"getNthHighestSalary({N})"])
  else:
    salary = sorted(unique_salaries, reverse=True)[N - 1]
    return pd.DataFrame([salary], columns=[f"getNthHighestSalary({N})"])

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