create table products_extended(
id INT primary key,
name TEXT,
category TEXT,
price DECIMAL,
in_stock BOOLEAN,
email_support TEXT
);

INSERT INTO products_extended (id, name, category, price, in_stock, email_support) VALUES
(1, 'iPhone 14', 'smartphone', 799, TRUE, 'iphone@apple.com'),
(2, 'MacBook Air', 'laptop', 1199, FALSE, NULL),
(3, 'Galaxy S22', 'smartphone', 699, TRUE, 'galaxy@support.com'),
(4, 'ThinkPad X1', 'laptop', 1399, TRUE, 'thinkpad@lenovo.com'),
(5, 'iPad Pro', 'tablet', 999, FALSE, 'ipad@apple.com'),
(6, 'Kindle Paperwhite', 'ebook_reader', 149, TRUE, NULL),
(7, 'Mi Band 7', 'smartwatch', 49, TRUE, 'miband@xiaomi.com'),
(8, 'Surface Pro', 'tablet', 1299, TRUE, 'surface@microsoft.com'),
(9, 'Honor Pad X9', 'tablet', 219, TRUE, 'honor@support.com'),
(10, 'Dell XPS 13', 'laptop', 1099, FALSE, 'dell@support.com');

select * from products_extended
where in_stock = true and category not in ('smartwatch', 'ebookreader') and price between 300 and 1300;

select name, category, price, price * 1.1 as price_with_markup, price * 1.2 as price_with_vat, coalesce(email_support, 'нет почты') as status
from  products_extended 
where in_stock = true and category not in ('smartwatch', 'ebookreader') and price between 300 and 1300;

select name, category, email_support, price * 1.25 as price_25, (price> 1000) as premium
from products_extended
where (price < 150 or price > 1200) and email_support is not null
order by premium;

select id, name, category, price 
from products_extended
where category in('smartphone', 'laptop', 'tablet') and name not like '%i%' and price between 500 and 1300
order by id desc;

select name, category, price, coalesce (email_support, 'нет поддержки') as comment
from products_extended
where email_support is null and in_stock is not null and price < 800;

select name, category, price, (price>1000) as premium
from products_extended
where (name like '%Pro%' or name like '%X%') and in_stock is true and price > 700
order by price desc;