How to Identify the On-Hand Quantity

select  ITEM_ID,
        sum(TARGET_QTY) quantity  
FROM(SELECT moqd.inventory_item_id item_id,           
     SUM (primary_transaction_quantity) target_qty
     FROM   mtl_onhand_quantities_detail moqd
     WHERE  moqd.organization_id = 204
     AND    moqd.owning_tp_type = DECODE (2, 2, 2, moqd.owning_tp_type)
     GROUP BY  moqd.inventory_item_id
  
UNION
    
SELECT mmt.inventory_item_id item_id,
       SUM (primary_quantity) target_qty        
FROM   mtl_material_transactions mmt,
       mtl_txn_source_types mtst,
       mtl_parameters mp
       WHERE   mmt.organization_id = 204 AND mp.organization_id = 204
                                         AND transaction_date >= (sysdate + 1)
       AND NVL (mmt.owning_tp_type, 2) =
                 DECODE (2, 2, 2, NVL (mmt.owning_tp_type, 2))
       AND mmt.transaction_source_type_id =
                    mtst.transaction_source_type_id
       AND NVL (mmt.logical_transaction, 2) <> 1
       GROUP BY  mmt.inventory_item_id)
       GROUP BY   ITEM_ID