584. Find Customer Referee

Description

Pandas Schema

data = [[1, 'Will', None], [2, 'Jane', None], [3, 'Alex', 2], [4, 'Bill', None], [5, 'Zack', 1], [6, 'Mark', 2]]
customer = pd.DataFrame(data, columns=['id', 'name', 'referee_id']).astype({'id':'Int64', 'name':'object', 'referee_id':'Int64'})

Table: Customer

+-------------+---------+
| Column Name | Type    |
+-------------+---------+
| id          | int     |
| name        | varchar |
| referee_id  | int     |
+-------------+---------+
In SQL, id is the primary key column for this table.
Each row of this table indicates
the id of a customer, their name, and the id of the customer who referred them.

Find the names of the customer that are either:

• referred by any customer with id != 2.
• not referred by any customer.
• Return the result table in any order.

The result format is in the following example.

Example 1:

• Input:

    Customer table:
    +----+------+------------+
    | id | name | referee_id |
    +----+------+------------+
    | 1  | Will | null       |
    | 2  | Jane | null       |
    | 3  | Alex | 2          |
    | 4  | Bill | null       |
    | 5  | Zack | 1          |
    | 6  | Mark | 2          |
    +----+------+------------+
    

• Output:

    +------+
    | name |
    +------+
    | Will |
    | Jane |
    | Bill |
    | Zack |
    +------+
    

💡 Hint 1:
Be careful of the NULL value

Submitted Code

import pandas as pd

def find_customer_referee(customer: pd.DataFrame) -> pd.DataFrame:
    # NaN 값은 0으로 변환
    return customer[customer["referee_id"].fillna(0) != 2][["name"]]

Runtime: 274 ms | Beats 83.58%
Memory: 66.79 MB | Beats 92.63%

referee_id 열의 값이 2가 아닌 경우에 모두 해당하기 때문에 NaN 값을 0으로 변경했다.

Other Solutions

1st

def find_customer_referee(customer: pd.DataFrame) -> pd.DataFrame:
    return customer[(customer['referee_id']!=2) | (customer['referee_id'].isna())][['name']]

| 연산자로 두 조건을 필터링했다.

2nd

select name from customer
where referee_id != 2 or referee_id is null;

MySQL 버전이다.