leetcode : 584. Find Customer Referee

leetcode : 584. Find Customer Referee

• [leetcode : 584. Find Customer Referee]

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다이어그램

erDiagram
    Customer {
        int id PK
        varchar name
        int referee_id FK
    }
    Customer ||--o{ Customer : "referee_id"

목표

Find the names of the customer that are not referred by the customer with id = 2.

referred id가 2가 아닌 행 출력

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문제 풀이

MySQL

--  Solution 1
SELECT NAME
FROM CUSTOMER
WHERE REFEREE_ID IS NULL OR REFEREE_ID != 2

• Solution 1
  • IS NULL | 조건 연산해주기

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Pandas

# Solution 1
def find_customer_referee(customer: pd.DataFrame) -> pd.DataFrame:
    return customer[~(customer['referee_id']==2) | customer['referee_id'].isnull()][['name']]

# Solution 2
def find_customer_referee(customer: pd.DataFrame) -> pd.DataFrame:
    return customer.drop(customer[customer['referee_id'] == 2].index)[['name']]

• Solution 1
  • OR 조건으로 두 조건을 묶어주기
• Solution 2
  • 또는, drop으로 2인 컬럼을 제거해주기

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코멘트

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