按反向分组2个数组值并汇总其他列

Question

我有一个数组，我需要按parentid和time按相反顺序进行分组。

Array
(
    [0] => Array
        (
            [0] => 1
            [ID] => 1
            [1] => 87898
            [totalsum] => 87898
            [2] => 1234
            [totalsuma] => 1234
            [3] => 2017-01-07
            [time] => 2017-01-07
            [4] => parent1
            [parentid] => parent1
            [5] => user1
            [username] => user1
        )

    [1] => Array
        (
            [0] => 2
            [ID] => 2
            [1] => 61405
            [totalsum] => 61405
            [2] => 0
            [totalsuma] => 0
            [3] => 2017-01-07
            [time] => 2017-01-08
            [4] => parent2
            [parentid] => parent2
            [5] => user2
            [username] => user2
        )

    [2] => Array
        (
            [0] => 3
            [ID] => 3
            [1] => 53824
            [totalsum] => 53824
            [2] => 0
            [totalsuma] => 0
            [3] => 2017-01-08
            [time] => 2017-01-08
            [4] => parent1
            [parentid] => parent1
            [5] => user1
            [username] => user1
        )

    [3] => Array
        (
            [0] => 4
            [ID] => 4
            [1] => 9313
            [totalsum] => 9313
            [2] => 0
            [totalsuma] => 0
            [3] => 2017-01-08
            [time] => 2017-01-08
            [4] => parent2
            [parentid] => parent2
            [5] => user3
            [username] => user3
        )

    [4] => Array
        (
            [0] => 5
            [ID] => 5
            [1] => 6420
            [totalsum] => 6420
            [2] => 0
            [totalsuma] => 0
            [3] => 2017-01-08
            [time] => 2017-01-08
            [4] => parent1
            [parentid] => parent1
            [5] => user4
            [username] => user4
        )

    [5] => Array
        (
            [0] => 6
            [ID] => 6
            [1] => 5826
            [totalsum] => 5826
            [2] => 0
            [totalsuma] => 0
            [3] => 2017-01-09
            [time] => 2017-01-09
            [4] => parent2
            [parentid] => parent2
            [5] => user2
            [username] => user2        )

)

首先，我需要按相反顺序按time进行分组，然后parentid进行归待totalsum和totalsuma

我需要在这样的表格中得到以下结果。

totalsum        totalsuma       parentid        time
------------------------------------------------------------
5826            0               parent2         2017-01-09
60244           0               parent1         2017-01-08
70718           0               parent2         2017-01-08
87898           1234            parent1         2017-01-07

我可以尝试使用以下代码，但没有获得预期的结果，但我可以解决一些更改，但只有time值，而不是time and parentid

if ( count($result) ) {
        $groups = array();
        $key = 0;
        foreach ($result as $item) {
            $key = $item['time'];
            if (!array_key_exists($key, $groups)) {
                $groups[$key] = array(
                    'totalsum' => $item['totalsum'],
                    'totalsuma' => $item['totalsuma'],
                    'parentid' => $item['parentid'],
                    'time' => $item['time'],
                );
            } else {
                $groups[$key]['totalsum'] = $groups[$key]['totalsum'] + $item['totalsum'];
                $groups[$key]['totalsuma'] = $groups[$key]['totalsuma'] + $item['totalsuma'];
                $groups[$key]['time'] = $groups[$key]['time'] + $item['time'];
            }
            $key++;
        }
    echo "<pre>";
    print_r($groups);
    echo "</pre>";
} else {
    echo "No rows returned.";
}

有人可以帮助实现这个目标吗？

提前致谢。