3. Find Customer Referee (584)

👉 https://leetcode.com/problems/find-customer-referee/?envType=study-plan&id=sql-i

Find Customer Referee - LeetCode

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🤔 문제 분석

1) Write an SQL query to report the names of the customer that are not referred by the customer with id = 2.

 

💡 풀이

SELECT name
FROM Customer
WHERE referee_id <> 2 OR referee_id IS NULL