Pull out query for campaign and children

lib/query/query_campaign_metrics.rb

@@ -13,8 +13,9 @@ module QueryCampaignMetrics
         ["donations", "donations.campaign_id=campaigns.id"],
         ["payments", "payments.donation_id=donations.id"]
       )
-      .where("campaigns.id IN (#{Qx.select("id").from('campaigns')
-                    .where("campaigns.id = $id OR campaigns.parent_campaign_id=$id", id: campaign_id).parse
+      .where("campaigns.id IN (#{QueryCampaigns
+                                     .get_campaign_and_children(campaign_id)
+                                     .parse
       })")
       .execute
       .last

lib/query/query_campaigns.rb

@@ -73,5 +73,12 @@ module QueryCampaigns
     )
   end
 
+  def self.get_campaign_and_children(campaign_id)
+    Qx.select("id")
+        .from('campaigns')
+        .where("campaigns.id = $id OR campaigns.parent_campaign_id=$id",
+               id: campaign_id)
+  end
+
 
 end