Hi,
Try this query:
SELECT T0.[ItemCode], T0.itemname, T0.[OnHand] FROM OITM T0 INNER JOIN OITB T1 ON T0.ItmsGrpCod = T1.ItmsGrpCod WHERE T0.[ItemCode] not in ( select T0.[Code] from ITT1 T0) and T0.[OnHand] >= 1 and T1.[ItmsGrpNam] = 'Component Item'
Thanks & Regards,
Nagarajan