Include products which are not in stock currently but below min. stock amount on stock overview page (fixes #69)

migrations/0038.sql

@@ -0,0 +1,27 @@
+DROP VIEW stock_missing_products;
+CREATE VIEW stock_missing_products
+AS
+SELECT
+	p.id,
+	MAX(p.name) AS name,
+	p.min_stock_amount - IFNULL(SUM(s.amount), 0) AS amount_missing,
+	CASE WHEN s.id IS NOT NULL THEN 1 ELSE 0 END AS is_partly_in_stock
+FROM products p
+LEFT JOIN stock s
+	ON p.id = s.product_id
+WHERE p.min_stock_amount != 0
+GROUP BY p.id
+HAVING IFNULL(SUM(s.amount), 0) < p.min_stock_amount;
+
+DROP VIEW stock_current;
+CREATE VIEW stock_current
+AS
+SELECT product_id, SUM(amount) AS amount, MIN(best_before_date) AS best_before_date
+FROM stock
+GROUP BY product_id
+
+UNION
+
+SELECT id, 0, null
+FROM stock_missing_products
+WHERE is_partly_in_stock = 0;