SQL> with left_table as (
  2          select 3 n from dual),
  3       table1 as (
  4          select rownum a from dual connect by level < 5),
  5       table2 as (
  6          select rownum + 2 b from dual connect by level < 5)
  7  select *
  8    from table1 t1
  9    left join table2 t2 on t1.a = t2.b and t2.b = (select n from left_table)
 10  ;
with left_table as (
*
ERROR at line 1:
ORA-01799: a column may not be outer-joined to a subquery

SQL>

SQL> with left_table as (
  2          select 3 n from dual),
  3       table1 as (
  4          select rownum a from dual connect by level < 5),
  5       table2 as (
  6          select rownum + 2 b from dual connect by level < 5)
  7  select *
  8    from (select *
  9            from table1 t1
 10            left join table2 t2 on t1.a = t2.b and t2.b = (select n from left_table))
 11  ;

         A          B
---------- ----------
         3          3
         1
         2
         4

SQL>