Joomla database query SELECT AS

I know this question is 6 months old, so you've probably found an answer or worked around it, but for anyone else who has a similar problem:

$query->select($db->quoteName(array('user_id','name'),array('uid','User-Name')));

If you only want to use an alias for some fields, just pass null in the array for the fields you don't want to alias, so for example:

$query->select($db->quoteName(array('user_id','name'),array(null,'User-Name')));

would give

"SELECT `user_id`, `name` AS `User-Name`"