SQL> create table t (val integer);

Table created.

SQL> create table a (val integer);

Table created.

SQL> create table b (val integer);

Table created.

SQL> insert into t select trunc(dbms_random.value(1,5)) from dual connect by level <= 10;

10 rows created.

SQL> insert into t values (0);

1 row created.

SQL> select val, count(*) cnt from t group by val order by val;
       VAL        CNT
---------- ----------
         0          1
         1          1
         2          4
         3          1
         4          4

5 rows selected.

SQL> insert first
  2  when cnt = 1 then into a values (val)
  3  else into b values (val)
  4  ( select val, count(*) over (partition by val) cnt from t )
  5  /

11 rows created.

SQL> select val from a order by val;
       VAL
----------
         0
         1
         3

3 rows selected.

SQL> select val, count(*) cnt from b group by val order by val;
       VAL        CNT
---------- ----------
         2          4
         4          4

2 rows selected.