diff --git a/anki/sched.py b/anki/sched.py
index 4dcfff3f0..ac4c29d43 100644
--- a/anki/sched.py
+++ b/anki/sched.py
@@ -863,7 +863,8 @@ your short-term review workload will become."""))
         "Put cards at the end of the new queue."
         self.col.db.execute(
             "update cards set type=0,queue=0,ivl=0 where id in "+ids2str(ids))
-        pmax = self.col.db.scalar("select max(due) from cards where type=0")
+        pmax = self.col.db.scalar(
+            "select max(due) from cards where type=0") or 0
         # takes care of mod + usn
         self.sortCards(ids, start=pmax+1)