create table MERGE_DELETE_TEST1 (I int primary key, J int, C varchar2(20))

create table MERGE_DELETE_TEST2 (I int primary key, J int, C varchar2(20))

insert into MERGE_DELETE_TEST1 values (1, 1, 'one')

insert into MERGE_DELETE_TEST1 values (2, 1, 'two')

insert into MERGE_DELETE_TEST1 values (3, 1, 'three')

insert into MERGE_DELETE_TEST1 values (4, 1, 'four')

insert into MERGE_DELETE_TEST2 values (2, 1, 'two')

insert into MERGE_DELETE_TEST2 values (3, 3, 'x')

insert into MERGE_DELETE_TEST2 values (4, null, 'dirigible')

insert into MERGE_DELETE_TEST2 values (99, 2, 'bobs your uncle')

commit

select t1.I, t1.J, t1.C, t2.I as X, t2.J as Y, t2.C as Z 
from MERGE_DELETE_TEST1 t1  
full join MERGE_DELETE_TEST2 t2  
    on t2.I = t1.I  
order by t1.I, X

merge into MERGE_DELETE_TEST2 tgt  
using ( 
    select t1.I, t1.J, t1.C, t2.I as X, t2.J as Y, t2.C as Z 
    from MERGE_DELETE_TEST1 t1  
    full join MERGE_DELETE_TEST2 t2  
        on t2.I = t1.I  
    ) src 
on ( 
    tgt.I = src.I  
    or src.I is null 
    ) 
when matched then  
    update set tgt.J = src.J, tgt.C = src.C  
        where tgt.I = src.I  
    delete where src.I is null and tgt.I is not null  
when not matched then  
    insert (I, J, C) 
    values (src.I, src.J, src.C)

select t1.I, t1.J, t1.C, t2.I as X, t2.J as Y, t2.C as Z 
from MERGE_DELETE_TEST1 t1  
full join MERGE_DELETE_TEST2 t2  
    on t2.I = t1.I  
order by t1.I, X

select * from MERGE_DELETE_TEST1 order by I

select * from MERGE_DELETE_TEST2 order by I

commit

drop table MERGE_DELETE_TEST1

drop table MERGE_DELETE_TEST2