select CUSTOMER_ID, OLD_VALUE, NEW_VALUE, MOMENT
from BM_ACTION_LOG
where ACTION_ID = 102
and STAFF_COMMENT = 'changed field `group_id`'

select al.CUSTOMER_ID, al.OLD_VALUE, al.NEW_VALUE, al.MOMENT
, al.NEW_VALUE as GROUP_ID
, al.MOMENT as DATE_BEG
, lead (al.MOMENT) over (partition by al.CUSTOMER_ID order by al.MOMENT) as DATE_END
from BM_ACTION_LOG al
join CUSTOMERS c on (c.CUSTOMER_ID = al.CUSTOMER_ID)
where al.ACTION_ID = 102
and al.STAFF_COMMENT = 'changed field `group_id`'
and al.CUSTOMER_ID = 78531
order by al.MOMENT

select al.CUSTOMER_ID, al.OLD_VALUE, al.NEW_VALUE, al.MOMENT
, nvl2(D.X, al.NEW_VALUE, null) as GROUP_ID
, nvl2(D.X, al.MOMENT, c.CREATE_DATE) as DATE_BEG
, nvl2(D.X, lead (al.MOMENT) over (partition by al.CUSTOMER_ID order by al.MOMENT), null) as DATE_END
from (select null as X from DUAL union all select 1 as X from DUAL) D
join CUSTOMERS c on (c.CUSTOMER_ID is not null)
left join BM_ACTION_LOG al on (al.CUSTOMER_ID = c.CUSTOMER_ID and D.X is not null)
where nvl2(D.X, al.ACTION_ID, 102) = 102
and nvl2(D.X, al.STAFF_COMMENT, 'changed field `group_id`') = 'changed field `group_id`'
and c.CUSTOMER_ID = 78531
order by al.MOMENT

select CUSTOMER_ID, VERSION, NEW_VALUE as GROUP_ID, DATE_BEG, DATE_END
from BM_ACTION_LOG
where ACTION_ID = 102
and STAFF_COMMENT = 'changed field `group_id`'
model
  partition by (CUSTOMER_ID)
  dimension by ((row_number() over (partition by CUSTOMER_ID order by MOMENT)) VERSION)
  measures(OLD_VALUE, NEW_VALUE, MOMENT DATE_BEG, lead (MOMENT) over (partition by CUSTOMER_ID order by MOMENT) DATE_END)
  rules
  (
    DATE_BEG[0]=null,
    DATE_END[0]=DATE_BEG[1],
    NEW_VALUE[0]=OLD_VALUE[1]
  )
order by CUSTOMER_ID, VERSION

select ...
from events
join
(
select CUSTOMER_ID, VERSION, NEW_VALUE as GROUP_ID, DATE_BEG, DATE_END
from BM_ACTION_LOG
...
) groups on (groups.customer_id = events.customer_id and nvl(groups.date_beg,date'1000-01-01') <= events.moment and nvl(groups.date_end,date'9999-01-01') > events.moment)
...

select ...
from events
join
(
select CUSTOMER_ID, VERSION, NEW_VALUE as GROUP_ID, nvl(DATE_BEG,DATE'1000-01-01') DATE_BEG, nvl(DATE_END,DATE'9999-01-01') DATE_END
from BM_ACTION_LOG
...
) groups on (groups.customer_id = events.customer_id and groups.date_beg <= events.moment and groups.date_end > events.moment)
...

with GH as
(
select CUSTOMER_ID, VERSION, NEW_VALUE as GROUP_ID, DATE_BEG, DATE_END
from BM_ACTION_LOG
where ACTION_ID = 102
and STAFF_COMMENT = 'changed field `group_id`'
model
  partition by (CUSTOMER_ID)
  dimension by ((row_number() over (partition by CUSTOMER_ID order by MOMENT)) VERSION)
  measures(OLD_VALUE, NEW_VALUE, MOMENT DATE_BEG, lead (MOMENT) over (partition by CUSTOMER_ID order by MOMENT) DATE_END)
  rules
  (
    DATE_BEG[0]=null,
    DATE_END[0]=DATE_BEG[1],
    NEW_VALUE[0]=OLD_VALUE[1]
  )
)
select C.CUSTOMER_ID
, C.GROUP_ID as CURRENT_GROUP_ID
, GH.GROUP_ID as HISTORY_GROUP_ID
, nvl(nullif(C.GROUP_ID,54),GH.GROUP_ID) as GROUP_ID
from CUSTOMERS C
left join GH
  on
  (
    GH.CUSTOMER_ID = C.CUSTOMER_ID
    and coalesce(GH.DATE_BEG, C.CREATE_DATE, DATE'1000-01-01') <= sysdate
    and coalesce(GH.DATE_END, C.STOP_DATE, DATE'9999-01-01') > sysdate
  )

with HISTORY as
(
  select ...
  , nvl2(L.ACTION_LOG_ID,
         decode(row_number() over (partition by L.CUSTOMER_ID order by L.MOMENT),
         1, sys.ODCINumberList(0,1),
         sys.ODCINumberList(1)), null) as DUPS
  from ...
)
select *
from HISTORY
left join TABLE(HISTORY.DUPS) DUPS on (0=0)

  , nvl2(L.ACTION_LOG_ID,
         decode(row_number() over (partition by L.CUSTOMER_ID order by L.MOMENT),
         1, sys.ODCINumberList(0,1),
         sys.ODCINumberList(1)), sys.ODCINumberList(null)) as DUPS

...
from HISTORY
left join
(
  select 1 as V, 0 as N from DUAL
  union all select 1, 1 from DUAL
) DUPS on (DUPS.V = HISTORY.VERSION)
...

--------------------------------------------------------------------------------------------------------------------------
| Id  | Operation                          | Name                        | Rows  | Bytes |TempSpc| Cost (%CPU)| Time     |
--------------------------------------------------------------------------------------------------------------------------
|   0 | SELECT STATEMENT                   |                             |   109K|    12M|       |  5670   (1)| 00:01:09 |
|   1 |  SQL MODEL ORDERED FAST            |                             |   109K|    12M|       |  5670   (1)| 00:01:09 |
|   2 |   WINDOW SORT                      |                             |   109K|    12M|    29M|  5670   (1)| 00:01:09 |
|   3 |    NESTED LOOPS OUTER              |                             |   109K|    12M|       |  2628   (1)| 00:00:32 |
|*  4 |     HASH JOIN RIGHT OUTER          |                             | 10921 |   426K|       |   231   (1)| 00:00:03 |
|   5 |      VIEW                          |                             |     6 |   126 |       |   214   (0)| 00:00:03 |
|   6 |       NESTED LOOPS                 |                             |     6 |   246 |       |   214   (0)| 00:00:03 |
|   7 |        NESTED LOOPS                |                             |     6 |   186 |       |   208   (0)| 00:00:03 |
|*  8 |         TABLE ACCESS BY INDEX ROWID| BM_ACTION_LOG               |     6 |   132 |       |   202   (0)| 00:00:03 |
|*  9 |          INDEX RANGE SCAN          | BM_ACTLOG_SUB_ACTION_ID_IDX |  4443 |       |       |    21   (0)| 00:00:01 |
|  10 |         TABLE ACCESS BY INDEX ROWID| BM_ENVELOP                  |     1 |     9 |       |     1   (0)| 00:00:01 |
|* 11 |          INDEX UNIQUE SCAN         | ENVELOPID_PK                |     1 |       |       |     0   (0)| 00:00:01 |
|  12 |        TABLE ACCESS BY INDEX ROWID | SERVICES                    |     1 |    10 |       |     1   (0)| 00:00:01 |
|* 13 |         INDEX UNIQUE SCAN          | SERVICES_PK                 |     1 |       |       |     0   (0)| 00:00:01 |
|  14 |      TABLE ACCESS FULL             | CUSTOMERS                   | 10921 |   202K|       |    16   (0)| 00:00:01 |
|  15 |     VIEW                           |                             |    10 |   840 |       |     0   (0)| 00:00:01 |
|* 16 |      FILTER                        |                             |       |       |       |            |          |
|* 17 |       TABLE ACCESS BY INDEX ROWID  | BM_ACTION_LOG               |     1 |   138 |       |   194   (0)| 00:00:03 |
|* 18 |        INDEX RANGE SCAN            | BM_ACTLOG_CUSTOMER_ID_IDX   |   360 |       |       |     5   (0)| 00:00:01 |
--------------------------------------------------------------------------------------------------------------------------
 
Predicate Information (identified by operation id):
---------------------------------------------------
 
   4 - access("A"."CUSTOMER_ID"(+)="C"."CUSTOMER_ID")
   8 - filter("L"."ACTION_ID"=50300)
   9 - access("L"."SUB_ACTION_ID"=5030001)
  11 - access("E"."ENVELOP_ID"="L"."TARGET_ID")
  13 - access("S"."SERVICE_ID"="E"."SERVICE_ID")
  16 - filter("C"."GROUP_ID"=54 OR "C"."GROUP_ID"=254 OR "C"."GROUP_ID"=255 OR "C"."GROUP_ID"=374)
  17 - filter("L"."STAFF_COMMENT"='changed field `group_id`' AND "L"."ACTION_ID"=102)
  18 - access("L"."CUSTOMER_ID"="C"."CUSTOMER_ID")

dimension by
(
  nvl2(L.ACTION_LOG_ID,row_number() over (partition by L.CUSTOMER_ID order by L.MOMENT),0) VERSION
)
...
rules
(
...
  GROUP_ID[0]=nvl("_OLD"[1],"_GROUP_ID"[0]),
...
)

  LAST_ID[VERSION]=case when GROUP_ID[VERSION] in (54,374,254,255) then LAST_ID[VERSION-1] else GROUP_ID[VERSION] end,
  LAST_ID[0]=GROUP_ID[0]