CREATE TABLE products (product_id NUMBER, parent_product_id NUMBER, product_category_code CLOB, date_product_first_available TIME, date_product_discontinued TIME, product_name CLOB, product_description CLOB, product_price NUMBER)
CREATE TABLE complaints (complaint_id NUMBER, product_id NUMBER, customer_id NUMBER, complaint_outcome_code CLOB, complaint_status_code CLOB, complaint_type_code CLOB, date_complaint_raised TIME, date_complaint_closed TIME, staff_id NUMBER)
CREATE TABLE staff (staff_id NUMBER, gender CLOB, first_name CLOB, last_name CLOB, email_address CLOB, phone_number CLOB)
CREATE TABLE customers (customer_id NUMBER, customer_type_code CLOB, address_line_1 CLOB, address_line_2 CLOB, town_city CLOB, state CLOB, email_address CLOB, phone_number CLOB)

Which products has been complained by the customer who has filed least amount of complaints?
SELECT DISTINCT t1.product_name FROM products AS t1 JOIN complaints AS t2 ON t1.product_id = t2.product_id JOIN customers AS t3 GROUP BY t3.customer_id ORDER BY COUNT(*) LIMIT 1
SELECT DISTINCT "t1"."product_name" FROM "products" "t1" CROSS JOIN "customers" "t3" JOIN "complaints" "t2" ON "t1"."product_id" = "t2"."product_id" GROUP BY "t3"."customer_id" ORDER BY COUNT(*) FETCH FIRST 1 ROWS ONLY