nilai per semester

<?php
/************************
created by   : CAHYA DSN
created date : 2013-01-02
status       : not tested
*************************/
//collecting data from previous POST
$nis        =isset($_POST['isi'])?$_POST['isi']:'';
$nip        =isset($_POST['nip'])?$_POST['nip']:'';
$isi        =isset($_POST['namakepala'])?$_POST['namakepala']:'';
$periode    =isset($_POST['thn'])?$_POST['thn']:'';
$tahunajaran=isset($_POST['tahunajaran'])?$_POST['tahunajaran']:'';
?>
<!DOCTYPE html>
<html>
<head>
<title>Data Nilai</title>
<style type="text/css">
body,table {font-family:arial,verdana, sans-serif; font-size:10pt;}
.left {float:left;}
.right {float:right;}
.clear {clear:both;}
.label {width:150px;font-weight:normal;}
.colon {width:40px;}
.data {width:150px;font-weight:bold;}
.header_sekolah {font-size:14pt;width:100%;}
.header_judul {font-size:18pt;width:100%;}
.container {width:100%;}
.dark {background-color:#eee;}
.light {background-color:#fff;}
</style>
</head>
<body>
<?php
if($nis){
  include("../library/koneksi.php");
?>
<div class="header_sekolah">
MADRASAH TSANAWIAH NEGERI SUBANG ANAK<br />
KABUPATEN TANAH DATAR<br />
JL. RAYA PADANG PANJANG - SOLOK
</div>
<div class="header_judul">DATA NILAI</div>
<?php
$sql="SELECT namasiswa, kelas FROM siswa WHERE nis = '".$nis."'";
$query = mysql_query($sql)or die ("Query failed with error: ".mysql_error());
$data = mysql_fetch_array($query);
?>
<div class="container">
  <div class="label left">NISN</div>
  <div class="colon left">:</div>
  <div class="data left"><?php echo $nis;?></div>
  <div class="label right">Tahun Ajaran :</div>
  <div class="data right"><?php echo $tahunajaran; ?></div>
  <div class="clear"></div>
  <div class="label left">Nama Siswa</div>
  <div class="colon left">:</div>
  <div class="data left"><?php echo $data['namasiswa'];?></div>
  <div class="clear"></div>
  <div class="label left">Kelas</div>
  <div class="colon left">:</div>
  <div class="data left"><?php echo $data['kelas'];?></div>
  <div class="clear"></div>
  <div class="datagrid">
  <table width="100%" border="0">
<?php
  $sql="SELECT n.nis, n.kodematapelajaran, n.nilaiMID, n.nilaiUAS, mp.namamatapelajaran, mp.semester
        FROM nilai n,matapelajaran mp
        WHERE n.kodematapelajaran=mp.kodematapelajaran
        AND n.nis = '".$nis."'
        ORDER BY mp.semester";
  $query = mysql_query($sql)or die ("Query failed with error: ".mysql_error());
  if(mysql_num_rows($query)){
    $i=0;
    $semester=0;
    while ($data = mysql_fetch_array($query)){
      if($semester!=$data['semester']){
        $semester=$data['semester'];
        echo "<tr><th colspan=\"5\"> SEMESTER $semester</th></tr>\n"
            ."<tr>\n"
            ."<th>KODE MATAPELAJARAN</th>\n"
            ."<th>NAMA MATAPELAJARAN</th>\n"
            ."<th>SEMESTER</th>\n"
            ."<th>NILAI MID</th>\n"
            ."<th>NILAI UAS</th>\n"
            ."</tr>\n";
      }
?>
<tr class="<?php echo $i%2==0?"dark":"light";?>">
  <td><?php echo $data['kodematapelajaran'];?></td>
  <td><?php echo $data['namamatapelajaran'];?></td>
  <td><?php echo $data['semester'];?></td>
  <td><?php echo $data['nilaiMID'];?></td>
  <td><?php echo $data['nilaiUAS'];?></td>
</tr>
<?php
    }// end while
    echo "<tr>\n"
        ."<td colspan=\"5\">\n"
        ."<a href=\"semua.php?page=cetak&nis=".$nis."&isi=".$isi."&nip=".$nip."&tahunajaran=".$tahunajaran."\" target=\"_blank\">\n"
        ."<img src=\"images/Printer1.png\" title=\"PRINT NILAI\"/>\n"
        ."</a></td></tr>\n";
  }else{
    echo "<tr><td colspan=\"5\">Data Not Found</td></tr>\n";
  }
?>
</table>
</div> <!-- container -->
<?php
} else{
  echo "please provide correct 'NIS' number";
}
?>
</body>
</html>