CREATE TABLE Staff (staff_id INT, gender VARCHAR, first_name VARCHAR, last_name VARCHAR, email_address VARCHAR, phone_number VARCHAR)
CREATE TABLE Customers (customer_id INT, customer_type_code VARCHAR, address_line_1 VARCHAR, address_line_2 VARCHAR, town_city VARCHAR, state VARCHAR, email_address VARCHAR, phone_number VARCHAR)
CREATE TABLE Complaints (complaint_id INT, product_id INT, customer_id INT, complaint_outcome_code VARCHAR, complaint_status_code VARCHAR, complaint_type_code VARCHAR, date_complaint_raised DATETIME, date_complaint_closed DATETIME, staff_id INT)
CREATE TABLE Products (product_id INT, parent_product_id INT, product_category_code VARCHAR, date_product_first_available DATETIME, date_product_discontinued DATETIME, product_name VARCHAR, product_description VARCHAR, product_price DECIMAL)

A pie chart about the average price of products that have each category code.
SELECT product_category_code, AVG(product_price) FROM Products GROUP BY product_category_code
SELECT "product_category_code", AVG("product_price") FROM "Products" GROUP BY "product_category_code"