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177. Nth Highest Salary

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

Change the 1 after OFFSET to N-1, but then MySQL will report an error and it is estimated that the operation is not supported. Then we can add a SET N = N-1 in front.

  • 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
  DECLARE M INT;
  SET M=N-1; # index issue
  RETURN (
      # Write your MySQL query statement below.
      SELECT DISTINCT Salary
      FROM Employee
      ORDER BY Salary DESC
      LIMIT 1
      OFFSET M
  );
END

All Problems

All Solutions