二維陣列：$taskData

Array
(
    [0] => Array
        (
            [area] => 1
            [winsFlag] => 7
            [count] => 3
        )

    [1] => Array
        (
            [area] => 1
            [winsFlag] => 3
            [count] => 2
        )

    [2] => Array
        (
            [area] => 1
            [winsFlag] => 5
            [count] => 2
        )

    [3] => Array
        (
            [area] => 2
            [winsFlag] => 6
            [count] => 2
        )

    [4] => Array
        (
            [area] => 2
            [winsFlag] => 3
            [count] => 2
        )

    [5] => Array
        (
            [area] => 3
            [winsFlag] => 7
            [count] => 3
        )

    [6] => Array
        (
            [area] => 3
            [winsFlag] => 1
            [count] => 1
        )

    [7] => Array
        (
            [area] => 4
            [winsFlag] => 2
            [count] => 1
        )

    [8] => Array
        (
            [area] => 4
            [winsFlag] => 2
            [count] => 1
        )

)
 

根據area相同將count相加

$item=[];
foreach($taskData as $k=>$v){
	if(!isset($item[$v['area']])){
	    $item[$v['area']] = $v;
	}else{
		$item[$v['area']]['count'] += $v['count'];
	}
}

結果：得到一個新的陣列 $item

Array
(
    [1] => Array
        (
            [area] => 1
            [winsFlag] => 7
            [count] => 7
        )

    [2] => Array
        (
            [area] => 2
            [winsFlag] => 6
            [count] => 4
        )

    [3] => Array
        (
            [area] => 3
            [winsFlag] => 7
            [count] => 4
        )

    [4] => Array
        (
            [area] => 4
            [winsFlag] => 2
            [count] => 2
        )

)