113.

[문제]

https://leetcode.com/problems/employees-whose-manager-left-the-company/description/

 

[풀이]

1. employee_id에 포함되지 않은 manager_id를 필터링하고

2. salary가 30000미만인 행들만 필터링해준다.

3. ~ 연산자를 사용해서  manager_id가 null임에도 필터링된 친구들을 dropna()로 날려버린다.

4. 정렬하고 조건에 맞게 열을 선택해서 반환한다.

 

Pandas

import pandas as pd

def find_employees(employees: pd.DataFrame) -> pd.DataFrame:
    cond1 = ~employees.manager_id.isin(employees['employee_id'])
    cond2 = employees.salary < 30000
    return employees[cond1 & cond2].sort_values('employee_id').dropna()[['employee_id']]

 

SQL

SELECT employee_id
FROM Employees
WHERE 
    salary < 30000
    AND manager_id NOT IN (SELECT employee_id FROM Employees)
ORDER BY employee_id;