Update sql in rails way

app/models/vote_on_issue.rb

@@ -1,10 +1,15 @@
 class VoteOnIssue < ActiveRecord::Base
   unloadable
-  
+
   # Every vote belongs to a user and an issue
   belongs_to :user
   belongs_to :issue
-
+
+  scope :left_join_user, -> { joins("LEFT JOIN users ON users.id = vote_on_issues.user_id").select("users.login") }
+  scope :up_voters,      -> { select(:vote_val).where("vote_val > ?", 0) }
+  scope :down_voters,    -> { select(:vote_val).where("vote_val < ?", 0) }
+  scope :order_by_login, -> { order("users.login ASC") }
+
   def self.getMyVote(issue)
     iRet = 0
     begin
@@ -15,30 +20,21 @@ def self.getMyVote(issue)
     end
     iRet
   end
-  
+
   def self.getUpVoteCountOnIssue(issue_id)
     where("issue_id = ? AND vote_val > 0", issue_id).count
   end
-  
+
   def self.getDnVoteCountOnIssue(issue_id)
     where("issue_id = ? AND vote_val < 0", issue_id).count
   end
 
   def self.getListOfUpVotersOnIssue(issue_id)
-    # this does load the users, but costly: One query for each user
-      # where("issue_id = ? AND vote_val > 0", issue_id)
-    # this does load the users, less costly: One query for all users
-      # includes(:user).where("issue_id = ? AND vote_val > 0", issue_id)
-      # where("issue_id = ? AND vote_val > 0", issue_id).includes(:user)
-    # joins users successfully, but still execs one query for each user 
-      # where("issue_id = ? AND vote_val > 0", issue_id).joins(:user)
-    # This does what I want, but I'd love to find out how to do this in rails...
-    find_by_sql( ["SELECT `vote_on_issues`.`vote_val` AS vote_val, `users`.`login` AS user_login FROM `vote_on_issues` LEFT JOIN `users` ON (`users`.`id` = `vote_on_issues`.`user_id`) WHERE (`issue_id` = ? AND `vote_val` > 0) ORDER BY user_login ASC", issue_id] )
+    VoteOnIssue.up_voters.left_join_user.order_by_login
   end
-  
+
   def self.getListOfDnVotersOnIssue(issue_id)
-    # see getListOfUpVotersOnIssue
-    find_by_sql( ["SELECT `vote_on_issues`.`vote_val` AS vote_val, `users`.`login` AS user_login FROM `vote_on_issues` LEFT JOIN `users` ON (`users`.`id` = `vote_on_issues`.`user_id`) WHERE (`issue_id` = ? AND `vote_val` < 0) ORDER BY user_login ASC", issue_id] )
+    VoteOnIssue.down_voters.left_join_user.order_by_login
   end
 
 end