Right Joins

-- OUR FIRST RIGHT JOIN (seems the same as a left join?)

SELECT * FROM customers
RIGHT JOIN orders
    ON customers.id = orders.customer_id;

-- ALTERING OUR SCHEMA to allow for a better example (optional)

CREATE TABLE customers(
    id INT AUTO_INCREMENT PRIMARY KEY,
    first_name VARCHAR(100),
    last_name VARCHAR(100),
    email VARCHAR(100)
);
CREATE TABLE orders(
    id INT AUTO_INCREMENT PRIMARY KEY,
    order_date DATE,
    amount DECIMAL(8,2),
    customer_id INT
);

-- INSERTING NEW DATA (no longer bound by foreign key constraint)

INSERT INTO customers (first_name, last_name, email) 
VALUES ('Boy', 'George', 'george@gmail.com'),
       ('George', 'Michael', 'gm@gmail.com'),
       ('David', 'Bowie', 'david@gmail.com'),
       ('Blue', 'Steele', 'blue@gmail.com'),
       ('Bette', 'Davis', 'bette@aol.com');
       
INSERT INTO orders (order_date, amount, customer_id)
VALUES ('2016/02/10', 99.99, 1),
       ('2017/11/11', 35.50, 1),
       ('2014/12/12', 800.67, 2),
       ('2015/01/03', 12.50, 2),
       ('1999/04/11', 450.25, 5);
 
INSERT INTO orders (order_date, amount, customer_id) VALUES
('2017/11/05', 23.45, 45),
(CURDATE(), 777.77, 109);




PT 2




--A MORE COMPLEX RIGHT JOIN





SELECT 
    IFNULL(first_name,'MISSING') AS first, 
    IFNULL(last_name,'USER') as last, 
    order_date, 
    amount, 
    SUM(amount)
FROM customers
RIGHT JOIN orders
    ON customers.id = orders.customer_id
GROUP BY first_name, last_name;





-- WORKING WITH ON DELETE CASCADE



CREATE TABLE customers(
    id INT AUTO_INCREMENT PRIMARY KEY,
    first_name VARCHAR(100),
    last_name VARCHAR(100),
    email VARCHAR(100)
);
 
CREATE TABLE orders(
    id INT AUTO_INCREMENT PRIMARY KEY,
    order_date DATE,
    amount DECIMAL(8,2),
    customer_id INT,
    FOREIGN KEY(customer_id) 
        REFERENCES customers(id)
        ON DELETE CASCADE
);
 
 
INSERT INTO customers (first_name, last_name, email) 
VALUES ('Boy', 'George', 'george@gmail.com'),
       ('George', 'Michael', 'gm@gmail.com'),
       ('David', 'Bowie', 'david@gmail.com'),
       ('Blue', 'Steele', 'blue@gmail.com'),
       ('Bette', 'Davis', 'bette@aol.com');
       
INSERT INTO orders (order_date, amount, customer_id)
VALUES ('2016/02/10', 99.99, 1),
       ('2017/11/11', 35.50, 1),
       ('2014/12/12', 800.67, 2),
       ('2015/01/03', 12.50, 2),
       ('1999/04/11', 450.25, 5);