Modernise query.

app/models/pool.rb

@@ -108,12 +108,12 @@ def transfer_post_to_parent(post_id, parent_id)
     def get_sample
       # By preference, pick the first post (by sequence) in the pool that isn't hidden from
       # the index.
-      PoolPost.find(:all, :order => "posts.is_shown_in_index DESC, nat_sort(pools_posts.sequence), pools_posts.post_id",
-                          :joins => "JOIN posts ON posts.id = pools_posts.post_id",
-                          :conditions => ["pool_id = ? AND posts.status = 'active' AND pools_posts.active", id]).each do |pool_post|
-        return pool_post.post if pool_post.post.can_be_seen_by?(Thread.current["danbooru-user"])
+      PoolPost.joins(:post)
+        .where(:pool_id => id, :active => true, :posts => { :status => "active" })
+        .order("posts.is_shown_in_index DESC, NAT_SORT(pools_posts.sequence), pools_posts.post_id")
+        .each do |pool_post|
+          return pool_post.post if pool_post.post.can_be_seen_by?(Thread.current["danbooru-user"])
       end
-      return rescue nil
     end
 
     def can_change_is_public?(user)