Question: Find the names of products that were bought by at least two distinct customers.
SQL: SELECT DISTINCT T3.product_name FROM customer_orders AS T1 JOIN order_items AS T2 ON T1.order_id  =  T2.order_id JOIN products AS T3 ON T2.product_id  =  T3.product_id GROUP BY T3.product_id HAVING COUNT (DISTINCT T1.customer_id)  >=  2