diff --git a/src/utils/transforms.lisp b/src/utils/transforms.lisp
index d2264d3..209c69d 100644
--- a/src/utils/transforms.lisp
+++ b/src/utils/transforms.lisp
@@ -211,7 +211,7 @@
     (integer string-or-integer)))
 
 (defun sqlite-timestamp-to-timestamp (date-string-or-integer)
-  (declare (type (or integer simple-string) date-string-or-integer))
+  (declare (type (or null integer simple-string) date-string-or-integer))
   (when date-string-or-integer
     (cond ((and (typep date-string-or-integer 'integer)
                 (= 0 date-string-or-integer))
diff --git a/test/sqlite/sqlite.db b/test/sqlite/sqlite.db
index e33bd3c..4a76fd6 100644
Binary files a/test/sqlite/sqlite.db and b/test/sqlite/sqlite.db differ