diff --git a/swh/scheduler/backend.py b/swh/scheduler/backend.py
--- a/swh/scheduler/backend.py
+++ b/swh/scheduler/backend.py
@@ -227,7 +227,9 @@
             where.append('next_run >= %s')
             args.append(after)
 
-        query = 'select * from task where ' + ' and '.join(where)
+        query = 'select * from task'
+        if where:
+            query += ' where ' + ' and '.join(where)
         if limit:
             query += ' limit %s :: bigint'
             args.append(limit)
diff --git a/swh/scheduler/tests/test_scheduler.py b/swh/scheduler/tests/test_scheduler.py
--- a/swh/scheduler/tests/test_scheduler.py
+++ b/swh/scheduler/tests/test_scheduler.py
@@ -370,6 +370,13 @@
             ret = self.backend.get_tasks(task['id'] for task in cur_tasks)
             self.assertCountEqual(ret, cur_tasks)
 
+    def test_search_tasks(self):
+        self._create_task_types()
+        t = utcnow()
+        tasks = self._tasks_from_template(TEMPLATES['git'], t, 100)
+        tasks = self.backend.create_tasks(tasks)
+        self.assertCountEqual(self.backend.search_tasks(), tasks)
+
     def test_filter_task_to_archive(self):
         """Filtering only list disabled recurring or completed oneshot tasks