Find Customer Referee
Amazon, Uber
Problem Statement
A marketing team needs to analyze customer acquisition sources. Specifically, they want to identify customers who were not introduced to the platform by a specific referee.
Write an SQL query to report the names of the customers that are not referred by the customer with ID 2.
Rules:
- Return the name column only.
- Customers with no referee (NULL values) must be included in the results.
- The order of the result does not matter.
Tests your understanding of
Basic SQL, Filtering, NULL Handling and Logical Operators
Input Tables
customer
| id(INTEGER) | name(VARCHAR) | referee_id(INTEGER) |
|---|---|---|
| 1 | Will | null |
| 2 | Jane | null |
| 3 | Alex | 2 |
| 4 | Bill | null |
| 5 | Zack | 1 |
| 6 | Mark | 2 |
Expected Output
| name(VARCHAR) |
|---|
| Will |
| Jane |
| Bill |
| Zack |
Tags
EasyBasic SQLFilteringNULL HandlingLogical Operators
5-10 min
72%