SQL interview question: Customers With No Orders
Inactive Customers Report
Marketing wants to identify customers who registered but never made a purchase for a win-back campaign.
Find all customers who have no orders.
Return customer_id, name, email, and signup_date. Use LEFT JOIN with NULL filtering or NOT EXISTS.
Skills: LEFT JOIN with NULL filtering
Tables
customers 12 rows
- customer_id integer PK
- name text
- email text
- city text
- signup_date text
| customer_id | name | city | signup_date | |
|---|---|---|---|---|
| 101 | Alice Mitchell | [email protected] | San Francisco | 2024-01-15 |
| 102 | Bob Chen | [email protected] | New York | 2024-02-20 |
| 103 | Carol Davis | [email protected] | Los Angeles | 2024-03-10 |
orders 15 rows
- order_id integer PK
- customer_id integer → customers
- order_date text
- total_amount real
- status text
| order_id | customer_id | order_date | total_amount | status |
|---|---|---|---|---|
| 1 | 101 | 2024-01-20 | 249.99 | delivered |
| 2 | 101 | 2024-03-15 | 1999.99 | delivered |
| 4 | 101 | 2024-09-05 | 79.99 | delivered |