title: Select distinct first character based on the string column
body: <p>In SQLite I have a table of contacts with one of the columns being <code>last_name</code>. How can I get unique set of first characters of all last names in the table? Something like <code>['a', 'b', 'd', 'f', 'w']</code>. It would help if query would be case insensitive. I'm using SQLite on Android. Thanks</p>