SQL> select * from t order by a;

A
----------
Atest
Btest
Dtest
Etest
Htest
Wtest
dtest

7 rows selected.

SQL> with data as (select ascii(upper(substr(a,1,1))) a_val,a from t) select * from data where a_val>67 order by a;

     A_VAL A
---------- ----------
        68 Dtest
        69 Etest
        72 Htest
        87 Wtest
        68 dtest

SQL>