compare products - Udemy

select p1.product_name, p1.unit_price,
	p2.product_name, p2.unit_price,
    p1.unit_price - p2.unit_price AS price_diff
from products p1 inner join products p2
	on p1.unit_price <> p2.unit_price
where ABS(p1.unit_price - p2.unit_price) < 0.25
	AND p1.product_name > p2.product_name
order by price_diff DESC;