public function parse_query(string $statement): ?array
  {
    if ( $this->parser === null ){
      $this->parser = new \PHPSQLParser\PHPSQLParser();
    }
    try {
      $r = $this->parser->parse($statement);
      if ( !count($r) ){
        return null;
      }
      if ( isset($r['BRACKET']) && (\count($r) === 1) ){
        return null;
      }
      return $r;
    }
    catch ( \Exception $e ){
      $this->log('Impossible to parse the query '.$statement);
    }
    return null;
  }