select C.CLIENTID, C.ZKPO, C.CLIENTNAME, E.ENTNAME, E.ENTID

from CLIENTS C, Ent E

where C.ENTID=E.ENTID
    and
    (
      (exists
        (select first 1 PS.PSID
         from PRODSALE PS, PRODSERVICE PServ, ONES_EXPORT_PROD OSEP
         where PS.CLIENTID=C.CLIENTID
         and PS.PRODID=OSEP.PRODID
         and PS.VIADILLER=0
         and PS.PSID=PServ.PSID
    
         and PServ.TODATE=
           (select max(PServ1.TODATE)
            from PRODSERVICE PServ1
            where PServ1.PSID=PS.PSID)

         and PServ.TODATE between :FromDate and :ToDate
        )
      )
    )