diff --git a/synapse/storage/room.py b/synapse/storage/room.py
index 198612cf1c69..9cfa19d8dc70 100644
--- a/synapse/storage/room.py
+++ b/synapse/storage/room.py
@@ -246,7 +246,7 @@ def _background_insert_retention(self, progress, batch_size):
         def _background_insert_retention_txn(txn):
             txn.execute(
                 """
-                SELECT r.room_id, e.json FROM rooms
+                SELECT rooms.room_id, events.json FROM rooms
                 LEFT OUTER JOIN current_state_events AS state ON (
                     rooms.room_id = state.room_id
                     AND state.type = '%s'