SELECT customer_id, first_name,
CASE WHEN country = 'USA' THEN 'United States of America' WHEN country = 'UK' THEN 'United Kingdom' ELSE 'Unknown Country'
END AS country_name
FROM Customers;

SELECT order_id, customer_id,
CASE WHEN amount >= 400 THEN (amount - amount * 10/100)
END AS offer_price
FROM Orders;

SELECT customer_id, first_name,
CASE WHEN age >= 18 THEN 'Allowed'
END AS can_vote
FROM Customers;