CREATE TABLE Accounts (account_id NUMBER, customer_id NUMBER, account_name VARCHAR2, other_account_details VARCHAR2)
CREATE TABLE Customers_Cards (card_id NUMBER, customer_id NUMBER, card_type_code VARCHAR2, card_number VARCHAR2, date_valid_from DATETIME, date_valid_to DATETIME, other_card_details VARCHAR2)
CREATE TABLE Financial_Transactions (transaction_id NUMBER, previous_transaction_id NUMBER, account_id NUMBER, card_id NUMBER, transaction_type VARCHAR2, transaction_date DATETIME, transaction_amount DOUBLE PRECISION, transaction_comment VARCHAR2, other_transaction_details VARCHAR2)
CREATE TABLE Customers (customer_id NUMBER, customer_first_name VARCHAR2, customer_last_name VARCHAR2, customer_address VARCHAR2, customer_phone VARCHAR2, customer_email VARCHAR2, other_customer_details VARCHAR2)

Show the number of cards in different card type code in a pie chart.
SELECT card_type_code, COUNT(card_type_code) FROM Customers_Cards GROUP BY card_type_code
SELECT "card_type_code", COUNT("card_type_code") FROM "Customers_Cards" GROUP BY "card_type_code"