diff --git a/schema.sql b/schema.sql
index 30a7166..8e790ac 100644
--- a/schema.sql
+++ b/schema.sql
@@ -24,3 +24,11 @@ create table if not exists games (
 create index if not exists nonposted_games
 on games(posted)
 where posted = 0;
+
+create trigger if not exists delete_old_states
+before insert on games
+begin
+       delete from games
+       where json ->> 'gamePk' = new.json ->> 'gamePk' and
+       json ->> 'status' ->> 'detailedState' != new.json ->> 'status' ->> 'detailedState';
+end;