diff --git a/datasette/views/database.py b/datasette/views/database.py
index 103bd575..bdd433cc 100644
--- a/datasette/views/database.py
+++ b/datasette/views/database.py
@@ -203,7 +203,12 @@ class QueryView(DataView):
         named_parameters=None,
         write=False,
     ):
-        database = tilde_decode(request.url_vars["database"])
+        database_route = tilde_decode(request.url_vars["database"])
+        try:
+            db = self.ds.get_database(route=database_route)
+        except KeyError:
+            raise NotFound("Database not found: {}".format(database_route))
+        database = db.name
         params = {key: request.args.get(key) for key in request.args}
         if "sql" in params:
             params.pop("sql")
diff --git a/tests/test_routes.py b/tests/test_routes.py
index 211b77b5..5ae55d21 100644
--- a/tests/test_routes.py
+++ b/tests/test_routes.py
@@ -94,6 +94,7 @@ async def test_db_with_route_databases(ds_with_route):
         ("/original-name/t", 404),
         ("/original-name/t/1", 404),
         ("/custom-route-name", 200),
+        ("/custom-route-name?sql=select+id+from+t", 200),
         ("/custom-route-name/t", 200),
         ("/custom-route-name/t/1", 200),
     ),