แผนภูมิกระจายของ customer_id เทียบกับ card id ตาม card_type_code ไม่จำเป็นต้องใช้ตารางทั้งหมด
Scatterplot of customer_id vs card id by card_type_codeIt is not neccessary to use all the tables.
 Financial_Transactions:  transaction_id [ INTEGER]  previous_transaction_id [ INTEGER]  account_id [ INTEGER]  card_id [ INTEGER]  transaction_type [ VARCHAR(15)]  transaction_date [ DATETIME]  transaction_amount [ DOUBLE]  transaction_comment [ VARCHAR(255)]  other_transaction_details [ VARCHAR(255)] 
SELECT card_id, customer_id FROM Customers_Cards GROUP BY card_type_code