排序...我想下面的数组以cat_name来排序
Array
(
    [1] => Array
        (
            [cat_id] => 1
            [cat_name] => Other
        )

    [2827511014] => Array
        (
            [cat_id] => 2827511014
            [cat_name] => mobile phone housing
        )

    [2827513014] => Array
        (
            [cat_id] => 2827513014
            [cat_name] => mobile phone other accessories
        )

    [2827516014] => Array
        (
            [cat_id] => 2827516014
            [cat_name] => PC Accessories
        )

    [2827518014] => Array
        (
            [cat_id] => 2827518014
            [cat_name] => Electronics
        )

    [3089502014] => Array
        (
            [cat_id] => 3089502014
            [cat_name] => Jewelry Accessories
            [child] => Array
                (
                    [3089509014] => Array
                        (
                            [cat_id] => 3089509014
                            [cat_name] => Necklace
                        )

                    [3089510014] => Array
                        (
         &nb