diff --git a/app/models/survey_answer.rb b/app/models/survey_answer.rb
index 58d792e..1e55407 100644
--- a/app/models/survey_answer.rb
+++ b/app/models/survey_answer.rb
@@ -10,9 +10,13 @@ class SurveyAnswer
   belongs_to :questionnaire_survey
   after_create do
     if self.questionnaire_survey
-      answer_group = SurveyAnswerGroup.where(:questionnaire_survey_id=>self.questionnaire_survey.id,:user=>user).first
+      info = {:questionnaire_survey_id=>self.questionnaire_survey.id,:user=>self.user}
+      if self.user.blank?
+        info[:survey_answer_ids] = [self.id]
+      end
+      answer_group = SurveyAnswerGroup.where(info).first
       if answer_group.nil?
-        answer_group = SurveyAnswerGroup.new(:questionnaire_survey_id=>self.questionnaire_survey.id,:user=>user_id)
+        answer_group = SurveyAnswerGroup.new(info)
       end
       answer_group.last_modified = self.updated_at
       answer_group.survey_answer_ids << self.id
diff --git a/app/views/admin/surveys/answer_sets.html.erb b/app/views/admin/surveys/answer_sets.html.erb
index 6e9508d..4d9a00f 100644
--- a/app/views/admin/surveys/answer_sets.html.erb
+++ b/app/views/admin/surveys/answer_sets.html.erb
@@ -33,7 +33,7 @@
 <h3><%= @survey.title %></h3>
 <div>
   <% if @is_answer_list %>
-    <h4><%=t('survey.taken_by')%>: <%=@user.member_name%></h4>
+    <h4><%=t('survey.taken_by')%>: <%=@user.member_name rescue "NA" %></h4>
   <% else %>
     <form id="survey_answer_search">
       <div>
diff --git a/config/routes.rb b/config/routes.rb
index 12ea176..4c4d266 100644
--- a/config/routes.rb
+++ b/config/routes.rb
@@ -6,14 +6,30 @@ Rails.application.routes.draw do
     surveys.each do |survey|
       group_data = survey.survey_answers.asc(:updated_at).group_by(&:user)
       group_data.each do |user_id,survey_answers|
-        answer_group = SurveyAnswerGroup.where(:questionnaire_survey_id=>survey.id,:user=>user_id).first
-        if answer_group.nil?
-          answer_group = SurveyAnswerGroup.new(:questionnaire_survey_id=>survey.id,:user=>user_id)
+        org_updated_at = survey_answers.map{|a| a.updated_at}
+        if user_id.blank?
+          survey_answers.each do |survey_answer|
+            info = {:questionnaire_survey_id=>survey.id,:user=>user_id,:survey_answer_ids=>[survey_answer.id]}
+            answer_group = SurveyAnswerGroup.where(info).first
+            if answer_group.nil?
+              info.delete(:survey_answer_ids)
+              answer_group = SurveyAnswerGroup.new(info)
+            end
+            answer_group.last_modified = survey_answer.updated_at
+            answer_group.survey_answer_ids = [survey_answer.id]
+            answer_group.save
+          end
+        else
+          info = {:questionnaire_survey_id=>survey.id,:user=>user_id}
+          answer_group = SurveyAnswerGroup.where(info).first
+          if answer_group.nil?
+            answer_group = SurveyAnswerGroup.new(info)
+          end
+          answer_group.last_modified = survey_answers.last.updated_at
+          answer_group.survey_answer_ids = survey_answers.map{|a| a.id}
+          answer_group.save
         end
-        answer_group.last_modified = survey_answers.last.updated_at
-        answer_group.survey_answer_ids = survey_answers.map{|a| a.id}
-        answer_group.save
-        survey_answers.each{|a| a.updated_at = a.created_at;a.save}
+        survey_answers.each_with_index{|a,i| a.updated_at = org_updated_at[i];a.save}
       end
       survey.already_fix_data = true
       survey.survey_questions.each do |q|