Index: date_api_sql.inc
===================================================================
--- date_api_sql.inc	(revision 531)
+++ date_api_sql.inc	(working copy)
@@ -878,7 +878,7 @@
     if (!empty($parts[0]['period'])) {
       $min_date = date_now();
       foreach ($parts[0]['period'] as $part => $value) {
-        date_modify($min_date, "$value $part");
+        date_modify($min_date, "-$value $part");
       }
       return array($min_date, $max_date);
     }
@@ -886,4 +886,4 @@
     $now = date_now();
     return array($now, $now);
  }
-}
\ No newline at end of file
+}