Optimization Showdown: Anti-Join Pattern

Pick better query to find customers with no orders. Query A: SELECT c.customer_id FROM customers c LEFT JOIN orders o ON o.customer_id = c.customer_id WHERE o.customer_id IS NULL; Query B: SELECT c.customer_id FROM customers c WHERE NOT EXISTS (SELECT 1 FROM orders o WHERE o.customer_id = c.customer_id);

customers(customer_id), orders(order_id, customer_id)