diff --git a/lib/tasks/statistic_subject_info.rake b/lib/tasks/statistic_subject_info.rake
index f7e6ca100..8b3199eae 100644
--- a/lib/tasks/statistic_subject_info.rake
+++ b/lib/tasks/statistic_subject_info.rake
@@ -132,7 +132,7 @@ namespace :subjects do
             ActiveRecord::Base.connection.execute sql
           end
         end
-        if str > 0
+        if str.size > 0
           sql = "REPLACE INTO subject_user_infos(#{column_value}) VALUES #{str.join(",")}"
           puts sql
           ActiveRecord::Base.connection.execute sql