1 files changed, 28 insertions, 3 deletions
diff --git a/db/migrate/20160603180330_remove_duplicated_notification_settings.rb b/db/migrate/20160603180330_remove_duplicated_notification_settings.rb
index c2fcac4c53d..fe1c863b5b9 100644
--- a/db/migrate/20160603180330_remove_duplicated_notification_settings.rb
+++ b/db/migrate/20160603180330_remove_duplicated_notification_settings.rb
@@ -1,7 +1,32 @@
 class RemoveDuplicatedNotificationSettings < ActiveRecord::Migration
   def up
-    execute <<-SQL
-      DELETE FROM notification_settings WHERE id NOT IN ( SELECT min_id from (SELECT MIN(id) as min_id FROM notification_settings GROUP BY user_id, source_type, source_id) as dups )
-    SQL
+    duplicates = exec_query(%Q{
+      SELECT user_id, source_type, source_id
+      FROM notification_settings
+      GROUP BY user_id, source_type, source_id
+      HAVING COUNT(*) > 1
+    })
+
+    duplicates.each do |row|
+      uid = row['user_id']
+      stype = connection.quote(row['source_type'])
+      sid = row['source_id']
+
+      execute(%Q{
+        DELETE FROM notification_settings
+        WHERE user_id = #{uid}
+        AND source_type = #{stype}
+        AND source_id = #{sid}
+        AND id != (
+          SELECT id FROM (
+            SELECT min(id) AS id
+            FROM notification_settings
+            WHERE user_id = #{uid}
+            AND source_type = #{stype}
+            AND source_id = #{sid}
+          ) min_ids
+        )
+      })
+    end
   end
 end