diff --git a/app/models/mailer.rb b/app/models/mailer.rb
index 44139fb03..7be526f41 100644
--- a/app/models/mailer.rb
+++ b/app/models/mailer.rb
@@ -126,7 +126,7 @@ class Mailer < ActionMailer::Base
     @homeworks = HomeworkAttach.where("user_id=#{user.id} and (created_at between '#{date_from}' and '#{date_to}')").order("created_at desc")
 
     # 查询user在课程。项目中发布的讨论帖子
-    messages = Message.find_by_sql("select DISTINCT * from messages where author_id = #{user.id} and (created_on between '#{date_from}' and '#{date_to}') order by created_on desc")
+    messages = Message.find_by_sql("select DISTINCT * from messages where (created_on between '#{date_from}' and '#{date_to}') order by created_on desc")
     @course_messages ||= []
     @project_messages ||= []
     unless messages.first.nil?