如果我需要这些键同时具有一个值（从数据库传递），如何将键添加到PHP数组中？

问题在这里：我正在尝试编写一个可以构成动态PHP数组的代码。我有一个空数组，需要在其中添加键及其值，这些值由MySQL服务器的do-while循环传递。以下php代码：

$result=mysqli_query($link,"SELECT products_id,voted,rating FROM      table_products $sorting LIMIT 6");
if(mysqli_num_rows($result)>0) {

$a = array();
do {

    $row = mysqli_fetch_array($result);
    $obj=$row['products_id'];
    $rating=$row['rating'];
    $voted=$row['voted'];



    array_push($a,array('obj'.$obj => array('rating' =>
        $rating, 'voted' => $voted)));

} while ($row = mysqli_fetch_array($result)
);}

$json = json_encode($a);
echo $json;

...给我这个json字符串：

[{"obj1":{"rating":"25","voted":"5"}},{"obj3":{"rating":"36","voted":"10"}},{"obj5":{"rating":"6","voted":"4"}}]

...但是我需要这个：

["obj1":{"rating":"25","voted":"5"},"obj3":{"rating":"36","voted":"10"},"obj5":{"rating":"6","voted":"4"}]

那么我该如何推动呢？

'obj'.$obj => array('rating' => $rating, 'voted' => $voted)

是否没有像我在代码中那样将其放置在单独的数组中？我只是不知道实现此目标的正确方法。