create table t1 (id number, 
                 version number, 
                 val varchar2(20), 
                 constraint t1_pk primary key (id, version))

insert into t1 (id, version, val) 
select 1 id, 0 version, 'A_1' val from dual union all 
select 2 id, 0 version, 'B_1' val from dual union all 
select 1 id, 1 version, 'A_2' val from dual union all 
select 3 id, 0 version, 'B_1' val from dual

CREATE MATERIALIZED VIEW LOG ON t1 
LOGGING  
WITH SEQUENCE, ROWID, (val) 
INCLUDING NEW VALUES

create materialized view t1_sub_mv1 
refresh fast on commit 
as 
  select id, 
         max(version) latest_version, 
         count(version) cnt_version, 
         count(*) cnt_all 
  from   t1 
  group by id

create materialized view log on t1_sub_mv1 
with rowid, sequence (id, latest_version, cnt_version, cnt_all) 
including new values

create materialized view t1_sub_mv2 
refresh fast on commit 
as 
  select id, 
         version, 
         max(val) max_val_per_id_version, 
         count(*) cnt_all 
  from   t1 
  group by id, 
           version

create materialized view log on t1_sub_mv2 
with rowid, sequence (id, max_val_per_id_version, cnt_all) 
including new values

create materialized view t1_main_mv 
refresh fast on commit 
as 
  select mv1.id, 
         mv1.latest_version, 
         mv2.max_val_per_id_version val_of_latest_version, 
         mv1.rowid mv1_rowid, 
         mv2.rowid mv2_rowid 
  from   t1_sub_mv1 mv1, 
         t1_sub_mv2 mv2 
  where  mv1.id = mv2.id 
  and    mv1.latest_version = mv2.version

select id, latest_version, val_of_latest_version from t1_main_mv

insert into t1 (id, version, val) 
select 4, 0, 'D_1' from dual union all 
select 4, 1, 'D_2' from dual

commit

select id, latest_version, val_of_latest_version from t1_main_mv

insert into t1 (id, version, val) 
select 4, 2, 'D_3' from dual

commit

select id, latest_version, val_of_latest_version from t1_main_mv

drop materialized view t1_main_mv

drop materialized view t1_sub_mv1

drop materialized view t1_sub_mv2

drop table t1