Optimization: Anti-Join Pattern

Interviewer prompt: Find products never ordered. Choose better pattern at scale. Query A: SELECT p.product_id FROM products p WHERE p.product_id NOT IN (SELECT oi.product_id FROM order_items oi); Query B: SELECT p.product_id FROM products p LEFT JOIN order_items oi ON p.product_id = oi.product_id WHERE oi.product_id IS NULL;