drop table aaa;
create table aaa (date_from date, date_to date, c1 integer, c2 integer, c3 integer);
drop table bbb;
create table bbb (date_from date, date_to date, c4 integer, c5 integer, c6 integer);
insert into aaa values (to_date('20010101','YYYYMMDD'),to_date('20010331','YYYYMMDD'),1,0,0);
insert into aaa values (to_date('20030601','YYYYMMDD'),to_date('20041231','YYYYMMDD'),7,0,3);
insert into aaa values (to_date('20080101','YYYYMMDD'),null,1,8,0);
insert into bbb values (to_date('20020101','YYYYMMDD'),to_date('20020731','YYYYMMDD'),1,0,0);
insert into bbb values (to_date('20030101','YYYYMMDD'),to_date('20040131','YYYYMMDD'),1,0,7);
insert into bbb values (to_date('20060101','YYYYMMDD'),null,1,0,4);
commit;

Data from aaa
1. 01/01/2001  31/03/2001  1   0   0
2. 01/06/2003  31/12/2004  7   0   3
3. 01/01/2008              1   8   0

Data from bbb
1. 01/01/2002  31/07/2002  1   0   0
2. 01/01/2003  31/01/2004  1   0   7
3. 01/01/2006              1   0   4

Periods to get 
/* 
01/01/2001 31/03/2001 - record 1 from aaa
01/01/2002 31/07/2002 - record 1 from bbb 
01/01/2003 31/05/2003 - date_from record 2 from bbb, date_to is calculated based on merging periods from table aaa and bbb. Since date_to for record 2 from bbb is 31/01/2004, but there are another records from aaa/bbb that are in that period, we need to split the records, that why date_to is 31/05/2003, that's day before 01/06/2003 - record 2 table aaa
01/06/2003 31/01/2004 - same as above logic, 01/06/2003 record 2 table aaa till 31/01/2004
01/02/2004 31/12/2004 - day after previous record (31/01/2004) 01/02/2004 till the last period 31/12/2004 - record 2 table aaa
01/01/2006 31/12/2007 - record 3 bbb till day before 01/01/2008(record 3 table aaa) 31/12/2007
01/01/2008            - last one, record 3 table aaa
*/

Same with business data :
/*
01/01/2001 31/03/2001  1   0   0           
01/01/2002 31/07/2002  1   0   0           
01/01/2003 31/05/2003  1   0   7           
01/06/2003 31/01/2004  7   0   3   1   0   7
01/02/2004 31/12/2004  7   0   3           
01/01/2006 31/12/2007  1   0   4           
01/01/2008             1   8   0   1   0   4
*/

WITH w0
AS (
 SELECT date_from date_, 'df' cat FROM aaa
  UNION
 SELECT date_from, 'df' FROM bbb
  UNION
 SELECT date_to date_, 'dt' cat FROM aaa
  UNION
 SELECT date_to, 'dt' FROM bbb
)
, w1 AS (
SELECT w0.*
     , LEAD(date_) OVER (ORDER BY date_) lead_dt
     , LEAD(cat) OVER (ORDER BY date_) lead_cat
  FROM w0
)
, w2 AS (
SELECT *
  FROM (
         SELECT date_ + CASE WHEN cat = 'dt' THEN 1 ELSE 0 END df
              , lead_dt - CASE WHEN lead_cat = 'df' THEN 1 ELSE 0 END dt
           FROM w1
       )
 WHERE 1=1
   AND df <= NVL(dt,df) 
)
SELECT w2.df
     , w2.dt
     , aaa.c1
     , aaa.c2
     , aaa.c3
     , bbb.c4
     , bbb.c5
     , bbb.c6
  FROM w2
  LEFT OUTER JOIN aaa
    ON 1=1
   AND ((w2.df BETWEEN aaa.date_from AND NVL(aaa.date_to,w2.df))
         OR
       (aaa.date_from BETWEEN w2.df AND NVL(w2.dt,aaa.date_from))
       )
  LEFT OUTER JOIN bbb
    ON 1=1
   AND ((w2.df BETWEEN bbb.date_from AND NVL(bbb.date_to,w2.df))
         or
       (bbb.date_from BETWEEN w2.df AND NVL(w2.dt,bbb.date_from))
       )
 WHERE c1 IS NOT NULL
    OR c2 IS NOT NULL
    OR c3 IS NOT NULL
    OR c4 IS NOT NULL
    OR c5 IS NOT NULL
    OR c6 IS NOT NULL
;