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⌨ Programming Easy SQL Joins

Customers Who Never Placed an Order

Question

Find all customers who have never placed any order. Return their full name and email.

💡 Use customers and orders tables.
SQL Editor
Solution
SELECT
  c.first_name || ' ' || c.last_name AS customer_name,
  c.email
FROM customers c
LEFT JOIN orders o ON c.customer_id = o.customer_id
WHERE o.order_id IS NULL;
Explanation: LEFT JOIN ensures all customers appear. Filter WHERE order_id IS NULL keeps only those with no matching order — this is the ANTI JOIN pattern.