ALTER TABLE `inventory_item_stock` ADD `unit_cost` DECIMAL(15,2) NOT NULL AFTER `max_stock`, ADD `cost` DECIMAL(15,2) NOT NULL AFTER `unit_cost`;
UPDATE inventory_item_stock SET inventory_item_stock.unit_cost = (SELECT billing_item_pricelists.price FROM billing_item_pricelists WHERE billing_item_pricelists.item_id = inventory_item_stock.item_id AND billing_item_pricelists.pricelist = 'COST');
UPDATE inventory_item_stock SET cost = unit_cost * stock;