No Oracle, você precisa definir explicitamente algum valor para obter dados ordenados; sem isso, você pode ter resultados diferentes toda vez que executar uma consulta.
Com seus dados, isso:
WITH table1 AS
(SELECT 1 rn, '1' col1 FROM DUAL UNION
SELECT 2 rn, '2' col1 FROM DUAL UNION
SELECT 3 rn, 'NO_PATTERN' col1 FROM DUAL UNION
SELECT 4 rn, 'RANDOM_STUFF' col1 FROM DUAL),
table2 AS
(SELECT 1 rn, 'aaa' col2 FROM DUAL UNION
SELECT 2 rn, '4' col2 FROM DUAL UNION
SELECT 3 rn, 'qwewqeq' col2 FROM DUAL UNION
SELECT 4 rn, 'UUUUUU' col2 FROM DUAL)
SELECT col1, col2, t1.rn
from (select row_number() over (order by rn) as rn, col1 from table1 ) t1
inner join
(select row_number() over (order by rn) as rn, col2 from table2 ) t2
on (t1.rn = t2.rn)
dá:
COL1 COL2 RN
------------ ------- ----------
1 aaa 1
2 4 2
NO_PATTERN qwewqeq 3
RANDOM_STUFF UUUUUU 4
Sem um ordenamento explícito, por exemplo, este
WITH table1 AS
(SELECT '1' col1 FROM DUAL UNION
SELECT '2' col1 FROM DUAL UNION
SELECT 'NO_PATTERN' col1 FROM DUAL UNION
SELECT 'RANDOM_STUFF' col1 FROM DUAL),
table2 AS
(SELECT 'aaa' col2 FROM DUAL UNION
SELECT '4' col2 FROM DUAL UNION
SELECT 'qwewqeq' col2 FROM DUAL UNION
SELECT 'UUUUUU' col2 FROM DUAL)
SELECT col1, col2, t1.rn
from (select rownum as rn, col1 from table1 ) t1
inner join
(select rownum as rn, col2 from table2 ) t2
on (t1.rn = t2.rn)
dá
COL1 COL2 RN
------------ ------- ----------
1 4 1
2 UUUUUU 2
NO_PATTERN aaa 3
RANDOM_STUFF qwewqeq 4
