Denormalization with overlapping time intervals

Question

The table keeps statuses for objects, along with times each status started and ended. Like:
ID   From   To   Status
===  ====   ==   ======
23   T1     T2    S1
23   T3     T4    S2
23   T5     T6    S3The statuses may start and end at arbitrary moments of time, and each object may have several statuses at the same time. So the time intervals in the above table may look like this:
T1------------T2
    T3----------------------T4
         T5----------T6So, for example, from T! to T3 the object has only S1, while from T5 to T2 it has all 3: S1, S2, and S3.
I need to denormalize the table and show in the same line all statuses the object is having at different time intervals, that is
ID   From   To   Status1  Status2  Status3
===  ====   ==   ======   =======  =======
23   T1     T3    S1
23   T3     T5    S1       S2
23   T5     T2    S1       S2       S3
23   T2     T6    S2       S3
23   T6     T4    S2

Answer 1

SQL> with t as (select trunc(sysdate) dt from dual),
  2       t1 as (select 23 ID, dt From_dt, dt+10 To_dt, 'S1' Status from t union all
  3              select 23 ID, dt+3 From_dt, dt+18 To_dt, 'S2' Status from t union all
  4              select 23 ID, dt+7 From_dt, dt+14 To_dt, 'S3' Status from t)
  5              select * from t1
  6  /
        ID FROM_DT     TO_DT       STATUS
        23 04.08.2007  14.08.2007  S1
        23 07.08.2007  22.08.2007  S2
        23 11.08.2007  18.08.2007  S3
SQL>
SQL> with t as (select trunc(sysdate) dt from dual),
  2       t1 as (select 23 ID, dt From_dt, dt+10 To_dt, 'S1' Status from t union all
  3              select 23 ID, dt+3 From_dt, dt+18 To_dt, 'S2' Status from t union all
  4              select 23 ID, dt+7 From_dt, dt+14 To_dt, 'S3' Status from t),
  5       t2 as (select id,from_dt begdt from t1
  6               union all
  7              select id,to_dt from t1),
  8       t3 as  (select t2.*, lead(begdt) over(partition by id order by begdt) enddt from t2)
  9       select t3.*,
10              (select status from t1 where t3.id=t1.id and greatest(t1.from_dt,t3.begdt)<least(t1.to_dt, t3.enddt) and t1.status='S1') Status1,
11              (select status from t1 where t3.id=t1.id and greatest(t1.from_dt,t3.begdt)<least(t1.to_dt, t3.enddt) and t1.status='S2') Status2,
12              (select status from t1 where t3.id=t1.id and greatest(t1.from_dt,t3.begdt)<least(t1.to_dt, t3.enddt) and t1.status='S3') Ststus3
13               from t3
14        where enddt is not null
15        order by 2
16  /
        ID BEGDT       ENDDT       STATUS1 STATUS2 STSTUS3
        23 04.08.2007  07.08.2007  S1             
        23 07.08.2007  11.08.2007  S1      S2     
        23 11.08.2007  14.08.2007  S1      S2      S3
        23 14.08.2007  18.08.2007          S2      S3
        23 18.08.2007  22.08.2007          S2     
SQL>PS
there's a problem in vizualization on the forum.
all GREATEST() < LEAST()