creating tables

CREATE TABLE customer
(
    customer_id VARCHAR(40) PRIMARY KEY,
    customer_name VARCHAR(40),
	city VARCHAR(20),
	state VARCHAR(20),
	country VARCHAR(20),
	region VARCHAR(20),
    segment VARCHAR(40),
    product_id VARCHAR(20)
);

CREATE TABLE product
(
    product_id VARCHAR(30) PRIMARY KEY,
    product_name VARCHAR(40),
	category VARCHAR(20),
	sub_category VARCHAR(20),
    sales INT,
	quantity INT,
	discount INT,
	profit INT,
    customer_id VARCHAR(40) REFERENCES customer(customer_id) ON DELETE SET NULL
);

SELECT * 
FROM product;

CREATE TABLE orders
(
    order_id VARCHAR(30) PRIMARY KEY,
	order_date DATE,
    shipping_mode VARCHAR (30),
    shipping_date DATE,
    product_id VARCHAR(30) REFERENCES product(product_id) ON DELETE SET NULL
);

ALTER TABLE customer
ADD postal_code INT