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