Database: tracking_orders_minus_1_0
Question: List the names of the customers who have once bought product "food".
SQL: select t1.customer_name from customers_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 where t3.product_name = 'food' group by t1.customer_id having count ( * ) >= 1