For each product with some problems, list the count of problems and the product id.
SELECT count(*) ,  T2.product_id FROM problems AS T1 JOIN product AS T2 ON T1.product_id = T2.product_id GROUP BY T2.product_id
SELECT count(*) ,  T2.product_id FROM problems AS T1 JOIN product AS T2 ON T1.product_id = T2.product_id GROUP BY T2.product_id
[{'count(*)': 4, 'product_id': 1}, {'count(*)': 2, 'product_id': 2}, {'count(*)': 3, 'product_id': 4}, {'count(*)': 1, 'product_id': 5}, {'count(*)': 1, 'product_id': 6}, {'count(*)': 1, 'product_id': 7}, {'count(*)': 1, 'product_id': 8}, {'count(*)': 1, 'product_id': 13}, {'count(*)': 1, 'product_id': 15}]