hi mr.ramasamy
for me here it is working fine & showing result of that particular item.
in what way u r saving it.
1. go to MENU 'TOOLS' -> 'QUERIES' -> 'QUERY GENERATOR' -> just click Execute'
2. in the opened Query Preview Window, Edit & copy the given below query
SELECT sum(T1.[quantity])[qt] FROM OINV T0 INNER JOIN INV1 T1 ON T0.DocEntry = T1.DocEntry WHERE month(T0.[DocDate]) = month(getdate())-1 and year(T0.[DocDate]) = year(getdate()) and t1.itemcode = $[POR1.ITEMCODE] group by t1.[itemcode]
3. Don't Execute, just Click 'SAVE' & save the query with any name under 'FMS' query Category.
4. Press 'Shift + ALT + F2' in desired Field[ Better select unused field in PO such as eg. u_mreqno[Material Req No] & assign the query to be auto refresh whenever itemcode changed
Rgds
Nagaraj