Question : SQL Substr Order

I have a select statement that uses substr

select distinct substr(value, 1, 1) from table

This query returns letters (i.,e, H, O, B, D).

I need those letters to be sorted alphabetically (B, D, H, O).

How can I do this with this query.  I tried adding "sort by value" and "order by value".  I got an SQL error for both.

Using Oracle 10g.

Answer : SQL Substr Order

select distinct substr(value, 1, 1) from table
order by 1;

or give it an alias

select distinct substr(value, 1, 1) letter from table
order by letter;