php获取数据库数据，构造数组嵌套报错。

while (!!$row = $result->fetch_assoc()) {
    while (!!$contract_row = $result_contract->fetch_assoc()) {
        $subarr['sublist'][] = array(
            's_c_name' => $contract_row['s_c_name'],
            's_c_modal' => $contract_row['s_c_modal']
        );
    }
    $arr['list'][] = array(
        'myname' => $row['myname'],
        'mybank' => $row['mybank'],
        'mybankNO' => $row['mybankNO'],
        's_orderID' => $_row['s_orderID'],
        'contract_records' => $subarr['sublist']
    );
}