CREATE TABLE Sales (
    id INT AUTO_INCREMENT,
    product VARCHAR(100) NOT NULL,
    quantity INT NOT NULL DEFAULT 0,
    fiscalYear SMALLINT NOT NULL,
    fiscalMonth TINYINT NOT NULL,
    CHECK(fiscalMonth >= 1 AND fiscalMonth <= 12),
    CHECK(fiscalYear BETWEEN 2000 and 2050),
    CHECK (quantity >=0),
    UNIQUE(product, fiscalYear, fiscalMonth),
    PRIMARY KEY(id)
);

INSERT INTO Sales(product, quantity, fiscalYear, fiscalMonth)
VALUES
    ('2001 Ferrari Enzo',140, 2021,1),
    ('1998 Chrysler Plymouth Prowler', 110,2021,1),
    ('1913 Ford Model T Speedster', 120,2021,1);

SELECT * FROM Sales;

CREATE TABLE SalesChanges (
    id INT AUTO_INCREMENT PRIMARY KEY,
    salesId INT,
    beforeQuantity INT,
    afterQuantity INT,
    changedAt TIMESTAMP NOT NULL DEFAULT CURRENT_TIMESTAMP
);

DELIMITER $$

CREATE TRIGGER after_sales_update
AFTER UPDATE
ON sales FOR EACH ROW
BEGIN
    IF OLD.quantity <> NEW.quantity THEN
        INSERT INTO SalesChanges(salesId,beforeQuantity, afterQuantity)
        VALUES(old.id, old.quantity, new.quantity);
    END IF;
END$$

DELIMITER ;


UPDATE Sales 
SET quantity = 350
WHERE id = 1;

SELECT * FROM SalesChanges;

SET SQL_SAFE_UPDATES=0;


UPDATE Sales 
SET quantity = CAST(quantity * 1.1 AS UNSIGNED);