Optimisation requete + opérateur IN

SELECT A.RefDate, 'Swap' AS Product, sum(A.BPV) AS BasePV, sum(abs(A.BPV)) AS AbsoluteBasePV FROM
(
SELECT p.ReferenceDate AS RefDate,
INS.MaturityDateAdj AS Mat, 
 LG.CurrencyID AS CCY,   
ROUND(LGD.InterestFixedRate,8) AS IFR, 
LG.InterestIndexID AS IID, 
sum(VTR.BasePV) AS BPV
               FROM panorama..InstrumentLeg LG,
                    panorama..InstrumentLeg LGD,
                    panorama..Instrument INS,
                    panorama..ValuationTabResults VTR,
                    panorama..PortfolioResults p,
                    panorama..PartitionMapData PMD                   
WHERE p.ResultsID = VTR.ResultsID
AND  INS.InstrumentID = LG.InstrumentID
AND  INS.InstrumentID = LGD.InstrumentID 
AND LG.LegType = 'Flt'
AND LGD.LegType = 'Fxd'
AND INS.InstrumentID = PMD.Key4
AND PMD.Key0 = 'Swap'
AND INS.VersionNumber = 0 
AND LG.VersionNumber = 0
AND LGD.VersionNumber = 0
AND VTR.UserPartitionID=PMD.PartitionCode
AND p.PortfolioID IN  (SELECT PortfolioID FROM RPTRISK_DeskPortfolioMapping WHERE DeskID='oblig') 
GROUP BY p.ReferenceDate,
INS.MaturityDateAdj,  
LG.CurrencyID, 
 ROUND(LGD.InterestFixedRate,8), 
LG.InterestIndexID 
) A
GROUP BY A.RefDate

p.PortfolioID IN  (SELECT PortfolioID FROM RPTRISK_DeskPortfolioMapping WHERE DeskID='oblig')

p.PortfolioID IN  ('ABOBLIG','PRIMOBLI') 
--Ces valeurs étant le resultat envoyé par (select PortfolioID from RPTRISK_DeskPortfolioMapping where DeskID='oblig')