これを試してください:
SELECT max(dbo.WOO.WOO_LastReportedHrsDate),dbo.PLT.PLT_ItemID, SUM(dbo.PLD.PLD_IssueQty) AS Issued, dbo.WKO.WKO_WorkOrderID, dbo.WKO.WKO_RequiredQty, dbo.WKO.WKO_CompleteQty,
dbo.WKO.WKO_RequiredQty - dbo.WKO.WKO_CompleteQty AS openbalance, dbo.PLT.PLT_QtyPerAssy,
(dbo.WKO.WKO_CompleteQty * dbo.PLT.PLT_QtyPerAssy - SUM(dbo.PLD.PLD_IssueQty)) * - 1 AS WIP, dbo.WKO.WKO_ItemID, dbo.WOO.WOO_StatusCode,
dbo.WOO.WOO_WorkCenterID
FROM dbo.PLT INNER JOIN
dbo.PLD ON dbo.PLT.PLT_RecordID = dbo.PLD.PLD_PLT_RecordID INNER JOIN
dbo.WKO ON dbo.PLT.PLT_WorkOrderID = dbo.WKO.WKO_WorkOrderID LEFT OUTER JOIN
dbo.WOO ON dbo.PLT.PLT_WorkOrderID = dbo.WOO.WOO_WorkOrderID
WHERE (dbo.WKO.WKO_StatusCode = N'Released') AND (dbo.PLT.PLT_ItemID = '9005-20-1794')
AND (dbo.WOO.WOO_LastReportedHrsDate IS NOT NULL) AND (dbo.WOO.WOO_StatusCode IS NOT NULL)
GROUP BY dbo.PLT.PLT_ItemID, dbo.WKO.WKO_WorkOrderID, dbo.WKO.WKO_RequiredQty, dbo.WKO.WKO_CompleteQty, dbo.PLT.PLT_QtyPerAssy, dbo.WKO.WKO_ItemID,
dbo.WOO.WOO_StatusCode, dbo.WOO.WOO_WorkCenterID
HAVING (SUM(dbo.PLD.PLD_IssueQty) = dbo.WKO.WKO_RequiredQty * dbo.PLT.PLT_QtyPerAssy)
ORDER BY dbo.WKO.WKO_WorkOrderID