SQL Query to get Quantity On Hand of any item

SELECT   item.segment1 item_code, item.description item_description,

         SUM (on_hand.on_hand) on_hand

    FROM mtl_system_items_b item, mtl_onhand_total_mwb_v on_hand

   WHERE item.organization_id = 4  --ORG ID

  AND item.inventory_item_id = on_hand.inventory_item_id

     AND on_hand.subinventory_code = 'XXX'  --sub inventory

     AND item.segment1 = 'XXXXX' ---item name

GROUP BY item.segment1, item.description;