medoo::column_push PHP Method

    protected function column_push($columns)
    {
        if ($columns == '*') {
            return $columns;
        }
        if (is_string($columns)) {
            $columns = array($columns);
        }
        $stack = array();
        foreach ($columns as $key => $value) {
            preg_match('/([a-zA-Z0-9_\\-\\.]*)\\s*\\(([a-zA-Z0-9_\\-]*)\\)/i', $value, $match);
            if (isset($match[1], $match[2])) {
                array_push($stack, $this->column_quote($match[1]) . ' AS ' . $this->column_quote($match[2]));
            } else {
                array_push($stack, $this->column_quote($value));
            }
        }
        return implode($stack, ',');
    }