В рельсах 3:
VideoLog.select("count(*), DATE(CONVERT_TZ(created_at, '+00:00', '-05:00')) as converted_date").\
where(:user_id => 19, :question_id => 96, :dashboard => 'player_question').\
group('converted_date')
В рельсах 2:
VideoLog.all(:select => "count(*), DATE(CONVERT_TZ(created_at, '+00:00', '-05:00')) as converted_date",
:conditions => {:user_id => 19, :question_id => 96, :dashboard => 'player_question'},
:group => 'converted_date')