我将错误从索引转换为进程“类mysqli_result的对象无法转换为int in”

Question

i got error casting in calculation square distance

i have to make simple sql program but i got problem in casting data

if (isset($_POST['hitung'])) {
  $sql = "select * from tb_keterangan";
  $result = $conn->query($sql);
        while ($row = $result->fetch_assoc()) {
    $d_modal            =$conn->query("select modal from tb_keterangan");
    $d_lahan            =$conn->query("select lahan from tb_keterangan");
    $d_indukan          =$conn->query("select jumlah_indukan from tb_keterangan");
    $d_produksi         =$conn->query("select jumlah_produksi from tb_keterangan");
    $d_keterangan       =$conn->query("select keterangan from tb_keterangan");

    $modal        =$_POST['modal'];
    $lahan        =$_POST['lahan'];
    $indukan      =$_POST['j_indukan'];
    $produksi     =$_POST['produksi'];
    $ket          =$_POST['keterangan'];

    $h_modal      =($d_modal - (int)$row['modal']);
    $h_lahan      =((int)$d_lahan - (int)$lahan);
    $h_indukan    =((int)$d_indukan - (int)$indukan);
    $h_produksi   =((int)$d_produksi - (int)$produksi);
    // $h_ket        =($d_keterangan - $ket);

    //pangkat
    $p_modal      =pow($h_modal,2);
    $p_lahan      =pow($h_lahan,2);
    $p_indukan    =pow($h_indukan,2);
    $p_produksi   =pow($h_produksi,2);
    // $p_ket        =pow($h_ket,2);



    $square_distance = $p_modal+$p_lahan+$p_indukan+$p_produksi;
    ?>

but the result calculation is appear

</div>

Answer 1

'$d_modal =$conn->query("select modal from tb_keterangan");

These are query variable which you are converting into (int) but you need to get the result from these variables as they are object returned by mysqli query.

Use mysqli_fetch functions and then convert it into int