Task: Text to Code
Input (English): For each product, return its id and the number of times it was ordered.
Output (English): SELECT count(*) ,  T3.product_id FROM orders AS T1 JOIN order_items AS T2 JOIN products AS T3 ON T1.order_id = T2.order_id AND T2.product_id = T3.product_id GROUP BY T3.product_id