CREATE TABLE problem_status_codes (problem_status_code TEXT, problem_status_description TEXT)
CREATE TABLE problem_category_codes (problem_category_code TEXT, problem_category_description TEXT)
CREATE TABLE product (product_id DECIMAL, product_name TEXT, product_details TEXT)
CREATE TABLE problems (problem_id DECIMAL, product_id DECIMAL, closure_authorised_by_staff_id DECIMAL, reported_by_staff_id DECIMAL, date_problem_reported TIME, date_problem_closed TIME, problem_description TEXT, other_problem_details TEXT)
CREATE TABLE staff (staff_id DECIMAL, staff_first_name TEXT, staff_last_name TEXT, other_staff_details TEXT)
CREATE TABLE problem_log (problem_log_id DECIMAL, assigned_to_staff_id DECIMAL, problem_id DECIMAL, problem_category_code TEXT, problem_status_code TEXT, log_entry_date TIME, log_entry_description TEXT, log_entry_fix TEXT, other_log_details TEXT)

For which product was there a problem reported by Christop Berge, with closure authorised by Ashley Medhurst? Return the product ids.
SELECT product_id FROM problems AS T1 JOIN staff AS T2 ON T1.reported_by_staff_id = T2.staff_id WHERE T2.staff_first_name = "Christop" AND T2.staff_last_name = "Berge" INTERSECT SELECT product_id FROM problems AS T1 JOIN staff AS T2 ON T1.closure_authorised_by_staff_id = T2.staff_id WHERE T2.staff_first_name = "Ashley" AND T2.staff_last_name = "Medhurst"
SELECT "product_id" FROM "problems" AS "T1" JOIN "staff" AS "T2" ON "Berge" = "T2"."staff_last_name" AND "Christop" = "T2"."staff_first_name" AND "T1"."reported_by_staff_id" = "T2"."staff_id" INTERSECT SELECT "product_id" FROM "problems" AS "T1" JOIN "staff" AS "T2" ON "Ashley" = "T2"."staff_first_name" AND "Medhurst" = "T2"."staff_last_name" AND "T1"."closure_authorised_by_staff_id" = "T2"."staff_id"