Menampilkan Data Dari Database

Gan ini kok tampil datanya ada 3 padahal di databse cuman 1

 <?php

  require_once 'core/init.php';
  require_once 'template/header.php';

  if (!isset($_SESSION['username'])) header('Location: login.php');

  $id = isset($_GET['id']) ? $_GET['id'] : null;

  if (isset($_GET['id']) ) {
    $id_siswa = id_siswa($id);
    while($row = mysqli_fetch_assoc($id_siswa)) {
      $nis = $row['nis'];
      $nama = $row['nama'];
      $kelas = $row['kelas'];
      $program = $row['program'];
    }
  }

  ?>

  <div class="row">
    <div class="col-sm-12">
      <h2>Data Siswa</h2>
      <div class="media">
        <img class="mr-3" src="template/assets/admin.png" alt="Generic placeholder image">
        <div class="media-body mb-4">
          <h4><label for="nis">NIS: <?=$nis;?></label></h4>
          <h4><label for="nama">Nama: <?=$nama;?></label></h4>
          <h4><label for="kelas">Kelas: <?=$kelas;?></label></h4>
          <h4><label for="program">Program: <?=$program;?></label></h4>
        </div>
      </div>
    </div>
    <div class="col-md-12 mt-4">
      <h2>Riwayat Siswa</h2>
    </div>
    <div class="col-md-12">
      <div class="table-responsive-sm">
        <table class="table table-hover">
          <tr class="bg-dark text-light">
            <td class="text-center" width="50px">NO</td>
            <td class="text-center" width="200px">TANGGAL</td>
            <td class="text-center" width="150px">KATEGORI</td>
            <td class="text-center" width="250px">TINDAKAN</td>
            <td class="text-center" width="400px">KETERANGAN</td>
            <td width="200px"></td>
          </tr>
          <?php if (isset($_GET['id']) ) {
            $id_history= id_history($id);
            $no = 0;
            while($row = mysqli_fetch_assoc($id_history) ) :
              $no++; ?>
          <tr>
            <td class="text-center"><?=$no;?></td>
            <td class="text-center"><?=$row['tanggal'];?></td>
            <td class="text-center"><?=$row['kategori'];?></td>
            <td class="text-center"><?=$row['tindakan'];?></td>
            <td class="text-center"><?=$row['keterangan'];?></td>
            <td>
              <a class="btn btn-primary" href="edit.php?id=<?= $row['id'];?>"><span data-feather="edit"></span> Edit</a>
              <a class="btn btn-danger" href="delete.php?id=<?= $row['id'];?>"><span data-feather="delete"></span> Delete</a>
            </td>
          </tr>
          <?php endwhile; } ?>
          <?=print_r($id_history);?>
        </table>
      </div>
    </div>
    <div class="col-md-12">
      <a class="btn btn-primary" id="button" href="add_history.php?id=<?=$_GET['id_siswa'];?>"><span data-feather="edit"></span> Tambah Data</a>
      <a class="btn btn-danger" href="students.php?kelas=<?=$_GET['kelas'];?>">Kembali</a>
    </div>
  </div>

<?php require_once 'template/footer.php'; ?>

Ini functionnya

 function id_history($id) {
    global $conn;
    $query = "SELECT tbl_siswa.id, tbl_riwayat.tanggal, tbl_riwayat.kategori, tbl_riwayat.tindakan, tbl_riwayat.keterangan
              FROM tbl_siswa LEFT JOIN tbl_riwayat ON $id = tbl_riwayat.id_siswa";
    $result = mysqli_query($conn, $query);
    return $result;
  }