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Jul 19, 2025
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task: #584 #76

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2 changes: 2 additions & 0 deletions README.md
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Expand Up @@ -34,6 +34,7 @@ Useful for preparing for technical interviews and improving your SQL skills.

### Select

- [584. Find Customer Referee](./leetcode/easy/584.%20Find%20Customer%20Referee.sql)
- [595. Big Countries](./leetcode/easy/595.%20Big%20Countries.sql)
- [1148. Article Views I](./leetcode/easy/1148.%20Article%20Views%20I.sql)
- [1683. Invalid Tweets](./leetcode/easy/1683.%20Invalid%20Tweets.sql)
Expand Down Expand Up @@ -112,6 +113,7 @@ Useful for preparing for technical interviews and improving your SQL skills.
- [197. Rising Temperature](./leetcode/easy/197.%20Rising%20Temperature.sql)
- [511. Game Play Analysis 1](./leetcode/easy/511.%20Game%20Play%20Analysis%201.sql)
- [577. Employee Bonus](./leetcode/easy/577.%20Employee%20Bonus.sql)
- [584. Find Customer Referee](./leetcode/easy/584.%20Find%20Customer%20Referee.sql)
- [586. Customer Placing the Largest Number of Orders](./leetcode/easy/586.%20Customer%20Placing%20the%20Largest%20Number%20of%20Orders.sql)
- [595. Big Countries](./leetcode/easy/595.%20Big%20Countries.sql)
- [596. Classes With at Least 5 Students](./leetcode/easy/596.%20Classes%20With%20at%20Least%205%20Students.sql)
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25 changes: 25 additions & 0 deletions leetcode/easy/584. Find Customer Referee.sql
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/*
Question 584. Find Customer Referee
Link: https://leetcode.com/problems/find-customer-referee/description/?envType=problem-list-v2&envId=database

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 not referred by the customer with id = 2.

Return the result table in any order.
*/

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