CREATE TABLE users (
	id int PRIMARY KEY, -- NOT NULL
	name varchar(100) NOT NULL,
	age int,
	email varchar(100),
	country varchar(2),
	is_active boolean,
	created_at timestamptz NOT NULL
);
	
CREATE TABLE products (
	id int PRIMARY KEY, 
	name varchar(100) NOT NULL,
	category varchar(50),
	price decimal(10,2) NOT NULL,
	in_stock BOOLEAN -- или int, потому что или на складе или не на складе
); 
	
CREATE TABLE orders (
	id int PRIMARY KEY,
	user_id int, 
	order_date timestamptz NOT NULL,
	status varchar(20)
);

CREATE TABLE order_items (
	order_id int,
	product_id int,
	quantity int NOT NULL,
	price_at_purchase decimal(10,2) NOT NULL,
	PRIMARY KEY (order_id, product_id)
);

INSERT INTO pmikhailov.users
(id, "name", age, email, country, is_active, created_at) VALUES
(1, 'Alice', 25, 'alice@example.com', 'US', TRUE, '2024-01-10 10:00:00'),
(2, 'Bob', 30, 'bob@example.com', 'UK', TRUE, '2024-02-05 09:30:00'),
(3, 'Carol', 27, 'carol@example.com', 'US', FALSE, '2024-03-01 15:20:00'),
(4, 'Diana', 22, 'diana@gmail.com', 'US', TRUE, '2024-01-12 08:15:00'),
(5, 'Evan', 35, 'evan@example.com', 'UK', TRUE, '2024-01-18 19:40:00'),
(6, 'Farida', 29, 'farida@example.com', 'KZ', TRUE, '2024-02-20 11:05:00'),
(7, 'George', 31, 'george+test@example.com', 'US', TRUE, '2024-03-05 16:45:00'),
(8, 'Helen', 24, NULL, 'UK', FALSE, '2024-03-06 08:20:00'),
(9, 'Ivan', 26, 'ivan@example.com', 'RU', TRUE, '2024-01-11 14:30:00'),
(10, 'Julia', 28, 'julia@example.com', 'US', TRUE, '2024-03-07 18:05:00');


INSERT INTO pmikhailov.products
(id, "name", category, price, in_stock) VALUES
(1, 'iPhone 15', 'Электроника', 80000, TRUE),
(2, 'Kindle', 'Электроника', 15000, TRUE),
(3, 'Кроссовки Nike', 'Одежда', 9000, TRUE),
(4, 'Кроссовки NoName', 'Одежда', 3000, FALSE),
(5, 'Наушники Pro', 'Электроника', 12000, TRUE),
(6, 'Фитнес-браслет', 'Гаджеты', 6000, TRUE),
(7, 'Подарочная карта', 'Сервисы', 1000, TRUE);

INSERT INTO pmikhailov.orders
(id, user_id, order_date, status) VALUES
(1, 1, '2025-01-10 12:00:00', 'paid'),
(2, 3, '2025-01-12 09:30:00', 'cancelled'),
(3, 1, '2025-01-15 18:20:00', 'paid'),
(4, 2, '2025-01-20 11:05:00', 'created'),
(5, 4, '2025-02-01 17:45:00', 'paid'),
(6, 5, '2025-02-10 10:10:00', 'refunded'),
(7, 7, '2025-03-01 09:00:00', 'paid'),
(8, 9, '2025-03-05 19:30:00', 'paid');

INSERT INTO pmikhailov.order_items
(order_id, product_id, quantity, price_at_purchase) VALUES
(1, 1, 1, 78000),
(1, 3, 2, 8500),
(2, 2, 1, 14000),
(3, 5, 1, 11000),
(3, 7, 1, 1000),
(4, 2, 1, 15000),
(5, 6, 1, 6000),
(6, 1, 1, 82000),
(7, 3, 1, 9000),
(8, 4, 2, 2800);

SELECT id, name, country, created_at, email 
FROM users 
ORDER BY created_at DESC, name ASC;

SELECT id, name, country
FROM users
WHERE country = 'US'
ORDER BY name ASC;

SELECT id, name, country
FROM users
WHERE country = 'UK'
ORDER BY name ASC;

SELECT id, name, email
FROM users u 
WHERE email IS NOT NULL 
ORDER BY name ASC;

SELECT DISTINCT lower(email)
FROM users u
WHERE email IS NOT null;

SELECT id, name, created_at 
FROM users
WHERE created_at >= '2024-02-05 09:30:00.000 +0100'
ORDER BY created_at DESC 
LIMIT 2 OFFSET 1;


/* Задача 1 */

SELECT 
	name, 
	category, 
	price,
	price * 1.3 AS price_with_markup,
	price * 1.5 AS price_with_vat
FROM 
	products p 
WHERE 
	in_stock IS TRUE 
	AND price BETWEEN 100 AND 1300;


/* Задача 2 */

SELECT 
	name,
	price,
	price * 0.85 AS price_with_discount 
FROM 
	products p 
WHERE 
	(price <= 100) OR (price >= 1000);


/* Задача 3 */

SELECT 
	id, 
	name, 
	category, 
	price
FROM 
	products p 
WHERE 
	category IN ('tablet', 'smartphone', 'mouse')
	AND price >= 100;


/* Задача 4 */

SELECT 
	name, 
	category, 
	price
FROM	
	products p
WHERE name NOT ILIKE '%iPhone%';


/* Задача 5 */

SELECT 
	name, 
	category, 
	price
FROM 
	products p 
WHERE 
	name NOT ILIKE '%pro%'
ORDER BY 
	price DESC;

SELECT 
	name, 
	category, 
	price
FROM 
	products p 
WHERE 
	name NOT ILIKE '%mx%';
ORDER BY 
	price DESC;