/*
Your team at JPMorgan Chase is preparing to launch a new credit card, and to gain some insights, you're analyzing how many credit cards were issued each month.

Write a query that outputs the name of each credit card and the difference in the number of issued cards
between the month with the highest issuance cards and the lowest issuance. Arrange the results based on the largest disparity.
*/

-- Create the table
CREATE TABLE credit_card_issuance (
    card_name VARCHAR(50) NOT NULL,
    issued_amount INT NOT NULL,
    issue_month TINYINT NOT NULL CHECK (issue_month BETWEEN 1 AND 12),
    issue_year YEAR NOT NULL,
    PRIMARY KEY (card_name, issue_month, issue_year)
);

-- Insert the data
INSERT INTO credit_card_issuance (card_name, issued_amount, issue_month, issue_year) VALUES
('Chase Freedom Flex', 55000, 1, 2021),
('Chase Freedom Flex', 60000, 2, 2021),
('Chase Freedom Flex', 65000, 3, 2021),
('Chase Freedom Flex', 70000, 4, 2021),
('Chase Sapphire Reserve', 170000, 1, 2021),
('Chase Sapphire Reserve', 175000, 2, 2021),
('Chase Sapphire Reserve', 180000, 3, 2021);

SELECT
  card_name,
  MAX(issued_amount) - MIN(issued_amount) AS difference
FROM credit_card_issuance
GROUP BY card_name
ORDER BY difference DESC;