Oracle 18c

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Create table TEST_RUA (CLASS VARCHAR2(100), ID_LL VARCHAR2(100), ID_UU VARCHAR2(100), TKR VARCHAR2(100), NAME VARCHAR2(100),Delta_Date Date)
BEGIN
INSERT INTO TEST_RUA VALUES ('Bond', 'BERF', 'GV9999B12M1', 'TKXX', 'TES_RES' ,'');
INSERT INTO TEST_RUA VALUES ('Bond', 'BERT', 'FV9999B12M3', 'BURR', 'PRS_RES','');
INSERT INTO TEST_RUA VALUES ('Bond', 'BREG', 'TV9999B12M4', 'CVKR', 'FRTG_OP','');
INSERT INTO TEST_RUA VALUES ('Bond', 'BREG', 'SQTUREGBFNO', null, 'BEGT_TU','');
END;
/
1 rows affected

Select * from TEST_RUA


CLASS
ID_LL
ID_UU
TKR
NAME
DELTA_DATE


Bond
BERF
GV9999B12M1
TKXX
TES_RES
null

Bond
BERT
FV9999B12M3
BURR
PRS_RES
null

Bond
BREG
TV9999B12M4
CVKR
FRTG_OP
null

Bond
BREG
SQTUREGBFNO
null
BEGT_TU
null


Create table TEST_RUA_MER (CLASS VARCHAR2(100), ID_LL VARCHAR2(100), ID_UU VARCHAR2(100), TKR VARCHAR2(100), NAME VARCHAR2(100), Delta_Date Date);
BEGIN
INSERT INTO TEST_RUA_MER VALUES ('Bond', 'BERF', 'GV9999B12M1', 'TKXX', 'TES_RES','');
INSERT INTO TEST_RUA_MER VALUES ('Bond', 'BERT', 'FV9999B12M3', 'BURR', 'PRS_RES','');
INSERT INTO TEST_RUA_MER VALUES ('Bond', 'BREG', 'TV9999B12M4', 'CVKR', 'MT_QUE','');
INSERT INTO TEST_RUA_MER VALUES ('Bond', 'BREG', 'LV9999B12F6', 'OPTQ', 'BWQT_UI','');
END;
/
1 rows affected

Select * from TEST_RUA_MER


CLASS
ID_LL
ID_UU
TKR
NAME
DELTA_DATE


Bond
BERF
GV9999B12M1
TKXX
TES_RES
null

Bond
BERT
FV9999B12M3
BURR
PRS_RES
null

Bond
BREG
TV9999B12M4
CVKR
MT_QUE
null

Bond
BREG
LV9999B12F6
OPTQ
BWQT_UI
null


merge into test_rua_mer d
using (
 select a.* 
    , case
      when target = 'D' and cnt_id = cnt_vals then 'D'
      when target = 'S' and cnt_id = 1 and cnt_vals = 1 then 'I'
      when target = 'S' and cnt_id = 2 and cnt_vals = 1 then 'U'
      else 'X' -- ignore
     end action
 from (
  select
    count(*) over (partition by id_ll, id_uu, tkr) cnt_id
  , count(*) over (partition by id_ll, id_uu, tkr, class, name) cnt_vals
  , max(rwid) over (partition by id_ll, id_uu, tkr) rwid 
  , class, id_ll, id_uu, tkr, name, target 
  from (
   select class, id_ll, id_uu, tkr, name, 'D' target, rowid rwid
   from test_rua_mer
   union all
   select class, id_ll, id_uu, tkr, name, 'S' , null
   from test_rua
  ) a
 ) a
) s
on (d.rowid = s.rwid)
when not matched then
 insert (d.class, d.id_ll, d.id_uu, d.tkr, d.name)
 values (s.class, s.id_ll, s.id_uu, s.tkr, s.name)
 where action = 'I'
when matched then
 update set 
  d.class = s.class,
  d.name  = s.name
 where action in ('D', 'U')  
 delete where action = 'D'; 
5 rows affected

Select * from TEST_RUA_MER


CLASS
ID_LL
ID_UU
TKR
NAME
DELTA_DATE


Bond
BREG
TV9999B12M4
CVKR
FRTG_OP
null

Bond
BREG
SQTUREGBFNO
null
BEGT_TU
null


merge into test_rua_mer d
using (
 select a.* 
    , case
      when target = 'D' and cnt_id = cnt_vals then 'D'
      when target = 'S' and cnt_id = 1 and cnt_vals = 1 then 'I'
      when target = 'S' and cnt_id = 2 and cnt_vals = 1 then 'U'
      else 'X' -- ignore
     end action
 from (
  select
    count(*) over (partition by id_ll, id_uu, tkr) cnt_id
  , count(*) over (partition by id_ll, id_uu, tkr, class, name) cnt_vals
  , max(rwid) over (partition by id_ll, id_uu, tkr) rwid 
  , class, id_ll, id_uu, tkr, name, target 
  from (
   select class, id_ll, id_uu, tkr, name, 'D' target, rowid rwid
   from test_rua_mer
   union all
   select class, id_ll, id_uu, tkr, name, 'S' , null
   from test_rua
  ) a
 ) a
) s
on (d.rowid = s.rwid)
when not matched then
 insert (d.class, d.id_ll, d.id_uu, d.tkr, d.name)
 values (s.class, s.id_ll, s.id_uu, s.tkr, s.name)
 where action = 'I'
when matched then
 update set 
  d.class = s.class,
  d.name  = s.name
 where action in ('D', 'U')  
 delete where action = 'D'; 
4 rows affected

Select * from TEST_RUA_MER


CLASS
ID_LL
ID_UU
TKR
NAME
DELTA_DATE


Bond
BERF
GV9999B12M1
TKXX
TES_RES
null

Bond
BERT
FV9999B12M3
BURR
PRS_RES
null


Alter table 
ORA-00903: invalid table name
CLASS	ID_LL	ID_UU	TKR	NAME	DELTA_DATE
Bond	BERF	GV9999B12M1	TKXX	TES_RES	null
Bond	BERT	FV9999B12M3	BURR	PRS_RES	null
Bond	BREG	TV9999B12M4	CVKR	FRTG_OP	null
Bond	BREG	SQTUREGBFNO	null	BEGT_TU	null