Customers Who Never Ordered

The marketing team wants to re-engage registered customers who have never placed an order.

Find every customer in customers with no row in orders.

Return columns customer_id, name. Row order does not matter.

Schema

CREATE TABLE customers (
  customer_id INTEGER PRIMARY KEY,
  name TEXT NOT NULL,
  signup_date TEXT NOT NULL
);
CREATE TABLE orders (
  order_id INTEGER PRIMARY KEY,
  customer_id INTEGER NOT NULL,
  amount REAL NOT NULL
);

Sample data

customers

customer_id	name	signup_date
1	Omar Siddiqui	2025-11-02
2	Priya Shah	2025-11-15
3	Quinn Murphy	2025-12-01
4	Rosa Alvarez	2026-01-09
5	Sami Yousef	2026-01-20

orders

order_id	customer_id	amount
100	1	45
101	1	99.9
102	3	12.5
103	5	230

Hint 1

A LEFT JOIN keeps every customer, filling the order columns with NULL when there is no match.

Hint 2

NOT EXISTS with a correlated subquery works too.

Good practice for: Data Analyst, Backend Developer, Digital Marketing Specialist, Business Analyst

SQL (SQLite)

Run checks your query on the sample data (Ctrl + '). Submit also checks hidden databases.