Hi Miguel,
Try:
SELECT T0.[ItemCode], T0.[ItemName], T1.[ItmsGrpNam], T2.[WhsCode], T2.[OnHand], T2.[AvgPrice] AS ' STD Cost', SUM(T2.[StockValue])
FROM OITM T0 INNER JOIN OITB T1 ON T0.[ItmsGrpCod] = T1.[ItmsGrpCod] INNER JOIN OITW T2 ON T0.[ItemCode] = T2.[ItemCode]
WHERE T2.[OnHand] <>'0'
GROUP BY T0.[ItemCode], T0.[ItemName], T1.[ItmsGrpNam], T2.[WhsCode], T2.[OnHand], T2.[AvgPrice]
Thanks,
Gordon