Below is an context that describes a sql query, paired with an question that provides further information. Write an answer that appropriately completes the request.  # noqa: E501
### Context:
CREATE TABLE problems (product_id VARCHAR); CREATE TABLE product (product_id VARCHAR)
### Question:
For each product which has problems, what are the number of problems and the product id?
### Answer:
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