0584 Find Customer Referee.md

584. Find Customer Referee

Table: Customer

Column Name	Type
id	int
name	varchar
referee_id	int

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.
Write an SQL query to report the names of the customer that are not referred by the customer with id = 2.
Return the result table in any order.

The query 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

solution

# Write your MySQL query statement below
SELECT
    name
FROM customer
WHERE referee_id != 2 OR referee_id IS NULL