diff --git a/roomserver/storage/postgres/events_table.go b/roomserver/storage/postgres/events_table.go
index 87b06a252..7321c1a45 100644
--- a/roomserver/storage/postgres/events_table.go
+++ b/roomserver/storage/postgres/events_table.go
@@ -73,7 +73,7 @@ CREATE TABLE IF NOT EXISTS roomserver_events (
 const insertEventSQL = "" +
 	"INSERT INTO roomserver_events (room_nid, event_type_nid, event_state_key_nid, event_id, reference_sha256, auth_event_nids, depth, is_rejected)" +
 	" VALUES ($1, $2, $3, $4, $5, $6, $7, $8)" +
-	" ON CONFLICT ON CONSTRAINT roomserver_event_id_unique" +
+	" ON CONFLICT ON CONSTRAINT roomserver_event_id_unique DO UPDATE" +
 	" SET is_rejected = $8" +
 	" RETURNING event_nid, state_snapshot_nid"
 
diff --git a/roomserver/storage/sqlite3/events_table.go b/roomserver/storage/sqlite3/events_table.go
index 8f84823c8..4d4056fd2 100644
--- a/roomserver/storage/sqlite3/events_table.go
+++ b/roomserver/storage/sqlite3/events_table.go
@@ -49,7 +49,8 @@ const eventsSchema = `
 const insertEventSQL = `
 	INSERT INTO roomserver_events (room_nid, event_type_nid, event_state_key_nid, event_id, reference_sha256, auth_event_nids, depth, is_rejected)
 	  VALUES ($1, $2, $3, $4, $5, $6, $7, $8)
-	  ON CONFLICT SET is_rejected = $8
+	  ON CONFLICT DO UPDATE
+	  SET is_rejected = $8
 	  RETURNING event_nid, state_snapshot_nid;
 `