public function limit($limit, $size = null) { if (isset($limit)) { if (!empty($size) && $limit != 0) { $this->limitPageIndex = $limit; $this->limitPageSize = $size; $this->limit = DBTool::conditions_getLimit($limit, $size); } else { if (strpos($limit, 'limit') !== false) { $this->limit = $limit; } else { $this->limit = ' limit ' . $limit; } } } return $this; }