How to fix results key from a joined query

[eluser]vps4[/eluser]

Code:

$query = $this->db->query('SELECT a.*, n.node_title FROM article AS a JOIN node AS n ON a.node_ID = n.ID WHERE a.ID = '.(int)$id.' LIMIT 1;');
if ($query->num_rows()) {
    $row = $query->row();
}
print_r($row);

WHY the result be

Code:

Array
(
    [article] => stdClass Object
        (
            [a.ID] => 1
            [a.node_ID] => 1
            [a.title] => the test title
            [a.content] => the test content
            [n.node_title] => category 1
        )
)

how can I fix it to

Code:

Array
(
    [article] => stdClass Object
        (
            [ID] => 1
            [node_ID] => 1
            [title] => the test title
            [content] => the test content
            [node_title] => category 1
        )
)