diff --git a/core/lib/Drupal/Core/Database/Connection.php b/core/lib/Drupal/Core/Database/Connection.php
index b7f1f32..7092acc 100644
--- a/core/lib/Drupal/Core/Database/Connection.php
+++ b/core/lib/Drupal/Core/Database/Connection.php
@@ -520,7 +520,7 @@ protected function filterComment($comment = '') {
    *   An associative array of options to control how the query is run. See
    *   the documentation for DatabaseConnection::defaultOptions() for details.
    *
-   * @return \Drupal\Core\Database\StatementInterface
+   * @return \Drupal\Core\Database\StatementInterface|int|null
    *   This method will return one of: the executed statement, the number of
    *   rows affected by the query (not the number matched), or the generated
    *   insert ID of the last query, depending on the value of
@@ -570,6 +570,9 @@ public function query($query, array $args = array(), $options = array()) {
       }
     }
     catch (\PDOException $e) {
+      // Most database drivers will return NULL here, but some of them
+      // (e.g. the SQLite driver) may need to re-run the query, so the return
+      // value will be the same as for static::query().
       return $this->handleQueryException($e, $query, $args, $options);
     }
   }
@@ -586,7 +589,10 @@ public function query($query, array $args = array(), $options = array()) {
    * @param array $options
    *   An associative array of options to control how the query is run.
    *
-   * @return null
+   * @return \Drupal\Core\Database\StatementInterface|int|null
+   *   Most database drivers will return NULL when a PDO exception is thrown for
+   *   a query, but some of them may need to re-run the query, so they can also
+   *   return a \Drupal\Core\Database\StatementInterface object or an integer.
    *
    * @throws \Drupal\Core\Database\DatabaseExceptionWrapper
    * @throws \Drupal\Core\Database\IntegrityConstraintViolationException