Hola
Prueba esto
SELECT distinct T0.AbsID 'Nro AG', T1.freetxt, T0.BpCode 'Rut', T0.BpName 'Nombre', t3.slpname, T0.StartDate, T0.EndDate, T1.Itemname, T1.PlanQty, T1.UnitPrice 'Precio', t1.cumQty, t1.cumamntlc 'Importe Acumulado', (t1.planQty * t1.unitprice) - t1.cumamntlc 'Importe Pendiente', T5.DocDate FROM OOAT T0 INNER JOIN OAT1 T1 ON T0.AbsID = T1.AgrNo inner join OCRD t2 on t0.bpcode = t2.cardcode inner Join OSLP t3 on t2.slpcode = t3.slpcode left join RDR1 t4 on t0.absid = t4.agrno left join ORDR T5 on T5.DocEntry=T4.DocEntry WHERE T0.Cancelled = 'N' And T0.TermDate IS NULL
Saludos