SELECT concat(first_name,' ',last_name) as Name, ItemName, ItemPrice
FROM
(
  SELECT customer_id as id
  FROM pos_sales
  WHERE warehouse_sale = 1
) as CID,
(
  SELECT id
  FROM pos_sales
  WHERE warehouse_sale = 1
) as SID,
(
  SELECT item_name as ItemName, id
  FROM pos_items
) as ItemNames,
(
  SELECT item_id, item_unit_price as ItemPrice, sale_id
  FROM pos_sales_items
) as SaleItems,
pos_customers
WHERE  pos_customers.id = CID.id
AND    SID.id = SaleItems.sale_id
AND    SaleItems.item_id = ItemNames.id