SQL> ed
Wrote file afiedt.buf

  1  with dogovor(filmid,client_id,vidacha,vozvrat) as (
  2    select 1,1,date '2017-01-30',date '2017-02-22' from dual union all
  3    select 1,2,date '2017-01-20',date '2017-01-20' from dual union all
  4    select 1,3,date '2018-01-15',date '2018-03-16' from dual union all
  5    select 1,4,date '2017-02-20',date '2018-02-02' from dual union all
  6    select 2,1,date '2010-01-20',date '2018-04-01' from dual
  7  )
  8  ,film (filmid,namef,stoimost_prok) as (
  9    select 1,'Операция Ы',10 from dual union all
 10    select 2,'Avatar',15 from dual )
 11  --
 12  select
 13    RESULT,"доход"
 14  from (
 15    select
 16        upper (f.namef) as RESULT
 17       ,(sum(least(last_day(vidacha),vozvrat)-vidacha+1) over (partition by d.filmid))*stoimost_prok  "доход"
 18    from film f,dogovor d
 19    where f.filmid = d.filmid and to_char (d.vidacha,'MM') = '01'
 20    order by count(*) over (partition by d.filmid) desc)
 21* where rownum < 2
SQL> /

RESULT          доход
---------- ----------
ОПЕРАЦИЯ Ы        200

SQL>