Here is better looking query:
SELECT [PO Number]=RTRIM(A.PONUMBER),
[PO Line Number]=A.LineNumber,
[Item Number]=RTRIM(A.ITEMNMBR),
[Site ID]=RTRIM(A.LOCNCODE),
[Unit of Measure]=RTRIM(A.UOFM),
[Qty Ordered]=A.QTYORDER,
[Qty Canceled]=A.QTYCANCE,
[Qty Invoiced]=ISNULL(B.QTYINVCD,0),
[Qty Rejected]=ISNULL(B.QTYREJ,0),
[Qty Replaced]=ISNULL(B.QTYREPLACED,0),
[Qty Shipped]=ISNULL(B.QTYSHPPD,0),
[Qty Remaining]=A.QTYORDER-A.QTYCANCE-ISNULL(B.QTYSHPPD,0)
FROM POP10110 A --Purchase Order Line Work
LEFT OUTER JOIN (
SELECT A.PONUMBER, A.POLNENUM, QTYINVCD=SUM(A.QTYINVCD), QTYSHPPD=SUM(A.QTYSHPPD), QTYREJ=SUM(A.QTYREJ), QTYREPLACED=SUM(A.QTYREPLACED)
FROM POP10500 A
GROUP BY A.PONUMBER ,A.POLNENUM
) B --Purchase Order Receiving Line Work
ON A.PONUMBER=B.PONUMBER AND A.ORD = B.POLNENUM
ORDER BY A.PONUMBER, A.LineNumber