CREATE TABLE Customers (customer_id NUMBER, customer_first_name VARCHAR2, customer_middle_initial VARCHAR2, customer_last_name VARCHAR2, gender VARCHAR2, email_address VARCHAR2, login_name VARCHAR2, login_password VARCHAR2, phone_number VARCHAR2, town_city VARCHAR2, state_county_province VARCHAR2, country VARCHAR2)
CREATE TABLE Products (product_id NUMBER, parent_product_id NUMBER, production_type_code VARCHAR2, unit_price NUMBER, product_name VARCHAR2, product_color VARCHAR2, product_size VARCHAR2)
CREATE TABLE Invoices (invoice_number NUMBER, order_id NUMBER, invoice_date DATETIME)
CREATE TABLE Accounts (account_id NUMBER, customer_id NUMBER, date_account_opened DATETIME, account_name VARCHAR2, other_account_details VARCHAR2)
CREATE TABLE Order_Items (order_item_id NUMBER, order_id NUMBER, product_id NUMBER, product_quantity VARCHAR2, other_order_item_details VARCHAR2)
CREATE TABLE Product_Categories (production_type_code VARCHAR2, product_type_description VARCHAR2, vat_rating NUMBER)
CREATE TABLE Financial_Transactions (transaction_id NUMBER, account_id NUMBER, invoice_number NUMBER, transaction_type VARCHAR2, transaction_date DATETIME, transaction_amount NUMBER, transaction_comment VARCHAR2, other_transaction_details VARCHAR2)
CREATE TABLE Orders (order_id NUMBER, customer_id NUMBER, date_order_placed DATETIME, order_details VARCHAR2)
CREATE TABLE Invoice_Line_Items (order_item_id NUMBER, invoice_number NUMBER, product_id NUMBER, product_title VARCHAR2, product_quantity VARCHAR2, product_price NUMBER, derived_product_cost NUMBER, derived_vat_payable NUMBER, derived_total_cost NUMBER)

What are the different product names, and what is the sum of quantity ordered for each product. Visualize by bar chart.
SELECT product_name, SUM(T1.product_quantity) FROM Order_Items AS T1 JOIN Products AS T2 ON T1.product_id = T2.product_id GROUP BY T2.product_name
SELECT "product_name", SUM("T1"."product_quantity") FROM "Order_Items" "T1" JOIN "Products" "T2" ON "T1"."product_id" = "T2"."product_id" GROUP BY "T2"."product_name"