Hi,
You have to link RDR1 and POR1 like:
FROM ORDR T0 INNER JOIN RDR1 T1 ON T0.DocEntry = T1.DocEntry left join OPOR T2 on T2.[DocNum] = T1.[PoTrgNum] INNER JOIN POR1 T3 ON T2.DocEntry = T3.DocEntry and t1.itemcode = t3.itemcode and T1.[PoLineNum] = T3.[LineNum]
Thanks & Regards,
Nagarajan