ManaPHP\Mvc\Model\QueryBuilder::groupBy PHP Метод

    public function groupBy($groupBy)
    {
        $r = '';
        foreach (explode(',', $groupBy) as $item) {
            $parts = explode(' ', trim($item));
            if (count($parts) === 1) {
                $by = trim($parts[0]);
            } else {
                $r = $groupBy;
                break;
            }
            if (preg_match('#^[a-z_][a-z0-9_.]*#i', $by) === 1) {
                $r .= preg_replace('#[a-z_][a-z0-9_]*#i', '[\\0]', $by) . ', ';
            }
        }
        $this->_group = substr($r, 0, -2);
        return $this;
    }