create table test
(
  id  int ,
  x   int
);

insert into test values (1,1);
insert into test values (1,2);
insert into test values (1,3);
insert into test values (1,4);

insert into test values (2,1);
insert into test values (2,2);
insert into test values (2,3);

insert into test values (3,1);
insert into test values (3,2);

SQL>   1  select id from
  2  (
  3  select id,listagg(x,',')  within group (order by x) as list from test group by id
  4  )
  5* where list =('1,2')
SQL> /

	ID
----------
	 3

select id from test where x = all (select level from dual connect by level <= 2);

SQL> def list=1,2,3
SQL> select id
  2  from test
  3  group by id
  4  having count(distinct x)=(select count(*) from table(sys.odcinumberlist(&list)))
  5  /
        ID
----------
         2

1 row selected.

SQL> def list=1,2
SQL> /
        ID
----------
         3

1 row selected.

insert into test values (4,1);
insert into test values (4,6);

SQL> var txt varchar2(100);
SQL> exec :txt := '1,2';

PL/SQL procedure successfully completed.

SQL> 
SQL> select *
  2  from
  3  (
  4   with data
  5   as
  6   (
  7    select
  8    trim( substr (txt,
  9    instr (txt, ',', 1, level  ) + 1,
 10    instr (txt, ',', 1, level+1)
 11    - instr (txt, ',', 1, level) -1 ) )
 12    as token
 13    from (select ','||:txt||',' txt
 14    from dual)
 15    connect by level <=
 16    length(:txt)-length(replace(:txt,',',''))+1
 17   )
 18   select id
 19   from test
 20   where id in (select id from test where x in (select * from data) )
 21   group by id
 22   having count(distinct x) = (select count(*) from data)
 23  )
 24  /

       ID
---------
        3
        4

where id in (select id from test where x in (select * from data) )

having count(distinct x) = (select count(*) from data)

select  id
  from  test
  group by id
  having set(cast(collect(x) as ku$_objnumset)) = ku$_objnumset(1,2)
/

        ID
----------
         3

SQL> 

select  id
  from  test
  group by id
  having set(cast(collect(x) as ku$_objnumset)) = ku$_objnumset(1,2)
     and count(*) = count(x)
/