define alphabet="'01'"
define M=4

create table alphabet (letter varchar2(1));
insert into alphabet values ('0');
insert into alphabet values ('1');

select t1.letter||t2.letter
from 
(select t1.letter||t2.letter as letter 
from 
alphabet t1,
alphabet t2) t1,

(select t1.letter||t2.letter as letter 
from 
alphabet t1,
alphabet t2) t2

-----------------------
Вечны налоги,
Смерть и потеря данных.
Что на этот раз?

SQL> select wordd
  2  from
  3  (select distinct replace(sys_connect_by_path(letter,'#'),'#') wordd
  4  from alphabet
  5  connect by level <= 4
  6  )
  7  where length(wordd) = 4
  8  /
 
WORDD
--------------------------------------------------------------------------------
0100
0001
0011
0110
1010
0000
0101
1000
1001
1100
1101
0010
0111
1110
1011
1111
 
16 rows selected
 
SQL> 

create table alphabet (letter varchar2(1));
insert into alphabet values ('0');
insert into alphabet values ('1');

define alphabet="01"
define M=4

column ch_count new_value ch_count

SELECT length('&alphabet') ch_count FROM dual;
set heading off
spool s.sql
prompt with s as (
SELECT 'select ''' || substr('&alphabet', LEVEL, 1) || ''' ch from dual ' ||
       decode(LEVEL, &ch_count, '', 'union all')
  FROM dual
CONNECT BY LEVEL <= &ch_count;
prompt )
prompt select 
SELECT 't' || LEVEL || '.ch' || decode(LEVEL, &m, ' word', '||')
  FROM dual
CONNECT BY LEVEL <= &m;
prompt from 
SELECT 's t' || LEVEL || decode(LEVEL, &m, ';', ',')
  FROM dual
CONNECT BY LEVEL <= &m;
spool off
set heading on
@s