CREATE TABLE Customers_cards (customer_id VARCHAR)
CREATE TABLE Customers (customer_first_name VARCHAR, customer_id VARCHAR)

Show the customer ids and firstname without a credit card.
SELECT customer_id, customer_first_name FROM Customers EXCEPT SELECT T1.customer_id, T2.customer_first_name FROM Customers_cards AS T1 JOIN Customers AS T2 ON T1.customer_id = T2.customer_id WHERE card_type_code = "Credit"
SELECT "customer_id", "customer_first_name" FROM "Customers" EXCEPT SELECT "T1"."customer_id", "T2"."customer_first_name" FROM "Customers_cards" AS "T1" JOIN "Customers" AS "T2" ON "T1"."customer_id" = "T2"."customer_id" WHERE "Credit" = "card_type_code"