SQL> create table test(a varchar2(20));

Table created

SQL> insert into test values('2');

1 row inserted

SQL> insert into test values('12');

1 row inserted

SQL> insert into test values('玲珑剔透');

1 row inserted

SQL> commit;

Commit complete

SQL> select * from test;

A
--------------------
2
12
玲珑剔透

SQL> select a from test where length(a)!=lengthb(a);

A
--------------------
玲珑剔透

SQL> select a from test where asciistr(a) not like '%%';

A
--------------------
2
12

SQL> select a from test where asciistr(a) like '%%';

A
--------------------
玲珑剔透