CREATE VIEW stock_current_location_content
AS
SELECT
	IFNULL(s.location_id, p.location_id) AS location_id,
	s.product_id,
	SUM(s.amount) AS amount,
	MIN(s.best_before_date) AS best_before_date,
	IFNULL((SELECT SUM(amount) FROM stock WHERE product_id = s.product_id AND location_id = s.location_id AND open = 1), 0) AS amount_opened
FROM stock s
JOIN products p
	ON s.product_id = p.id
GROUP BY IFNULL(s.location_id, p.location_id), s.product_id;