# Customers Without Orders

> Customers who have never ordered.

Canonical URL: <https://datadriven.io/problems/customers_without_orders>

Domain: SQL · Difficulty: medium · Seniority: L4

## Problem

The customers table and the transactions table are linked by customer id: the customer_id column in customers corresponds to the user_id column in transactions. Count how many customers have never placed a transaction. Return a single integer.

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