products_and_stocks.sql

SELECT p.id, 
       p.items,
       Ifnull(Sum(s.stock), 0) AS sumstock 
FROM   phpshop_products p
       left JOIN 
       (
           select warehouse_id,
           		  enabled,
           		  product_id,
           		  stock
           from phpshop_modules_warehouse_stocks
           where warehouse_id IN ( 0 ) 
     	   		  AND enabled = '1' 
       ) s
         ON p.id = s.product_id 
WHERE  p.id IN ( 1288, 863 )
group by p.id