Get Error from the same value added on the table php
<p>Hello every one this is simple problem. I am working on a PHP project reserve subject of student. When I click the subject from another table it display to other table dynamically,the problem is how to get the error with the same value that added on the table?</p>

<p>here is the code subject:</p>

<pre><code>$sql = mysql_query("SELECT * FROM tblsubjecschedule ORDER BY Subject");

$i=0;
$b =1;
while($row=mysql_fetch_assoc($sql) ){


echo "&lt;tr&gt;&lt;td&gt;".$row['Subject']."&lt;input type='hidden' name='subj[$i]' value=".$row['Subject']."&gt;&lt;/td&gt;
&lt;td&gt;".$row['Lec']."&lt;br/&gt;".$row['Lab']."&lt;input type='hidden' name='leclab[$i]' value=".$row['Lec']."&gt;&lt;input type='hidden' name='lab[$i]' value=".$row['Lab']."&gt;&lt;/td&gt;

&lt;td&gt;".$row['Descriptive']."&lt;input type='hidden' name='desc[$i]' value=".$row['Descriptive']."&gt;&lt;/td&gt;
&lt;td&gt;".$row['Day']."&lt;br/&gt;".$row['Labday']."&lt;input type='hidden' name='daylabday[$i]' value=".$row['Day']."&gt;&lt;input type='hidden' name='labday[$i]' value=".$row['Labday']."&gt;&lt;/td&gt;

&lt;td&gt;".$row['LecTime']."&lt;br/&gt;".$row['LabTime']."&lt;input type='hidden' name='lectlabt[$i]' value=".$row['LecTime']."&gt;&lt;input type='hidden' name='labtime[$i]' value=".$row['LabTime']."&gt;&lt;/td&gt;

&lt;td&gt;".$row['Room']."&lt;br/&gt;".$row['Labroom']."&lt;input type='hidden' name='roomlabroom[$i]' value=".$row['Room']."&gt;&lt;input type='hidden' name='labroom[$i]' value=".$row['Labroom']."&gt;&lt;/td&gt;

&lt;td&gt;&lt;input id='send' name='reserv[$i]' type='submit' value='Add' onclick='addRow('myTable')' /&gt; &lt;/td&gt;&lt;/tr&gt;";

$i++;


}
  if (isset($_POST['reserv'])){
 if(!empty($_POST['reserv'])){
         $a = current(array_keys($_POST['reserv']));
  $subj=$_POST['subj'][$a];
 $leclab=$_POST['leclab'][$a];
 $lab=$_POST['lab'][$a];
 $labday=$_POST['labday'][$a];
 $desc=$_POST['desc'][$a];
 $daylab=$_POST['daylabday'][$a];
 $lectlabt=$_POST['lectlabt'][$a];
 $labtime=$_POST['labtime'][$a];
 $roomLabroom=$_POST['roomlabroom'][$a];
 $labroom=$_POST['labroom'][$a];



    }
    }


?&gt;
</code></pre>

<p>and here is the code that display the subject added:</p>

<pre><code>&lt;table border="1" id="myTable" style='width: 900px;'&gt;

&lt;thead&gt;
&lt;tr&gt;
    &lt;th&gt;SubjectCode &lt;th&gt;Units &lt;th&gt;Time &lt;th&gt;Day &lt;th&gt;Room&lt;/th&gt; 
&lt;/tr&gt;
&lt;/thead&gt;

 &lt;?php
    if(isset($_POST['reserv'])){
         $_SESSION["S[]"]=array();
                $_SESSION["lec[]"]=array();
                $_SESSION["lab[]"]=array();
                $_SESSION["Day[]"]=array();
            $_SESSION["lday[]"]=array();
            $_SESSION["lect[]"]=array();
                $_SESSION["labt[]"]=array();
            $_SESSION["room[]"]=array();
            $_SESSION["lroom[]"]=array();
                if (isset($_SESSION["counter"])){
                    $_SESSION["counter"]=$_SESSION["counter"]+1;
                    $counter=$_SESSION["counter"];
                }else{$_SESSION["counter"]=0;
                    $counter=$_SESSION["counter"];
                }

                    $counter=$_SESSION["counter"];


                            $_SESSION["S['$counter']"]=$subj;
                         $_SESSION["lec['$counter']"]=$leclab;
                         $_SESSION["lab['$counter']"]=$lab;
                         $_SESSION["Day['$counter']"]=$daylab;
                          $_SESSION["lday['$counter']"]=$labday;
                         $_SESSION["lect['$counter']"]=$lectlabt;
                         $_SESSION["labt['$counter']"]=$labtime;
                         $_SESSION["room['$counter']"]=$roomLabroom;
                         $_SESSION["lroom['$counter']"]=$labroom;




            $c=0;
            while($c&lt;=$counter){
                if($_SESSION["S['$c']"]==""){echo "-";}

            echo "&lt;tr&gt;&lt;td&gt;".$_SESSION["S['$c']"] . "&lt;/td&gt;
            &lt;td&gt;".$_SESSION["lec['$c']"] . "&lt;br/&gt;".$_SESSION["lab['$c']"] . "&lt;/td&gt;
            &lt;td&gt;".$_SESSION["lect['$c']"] . "&lt;br/&gt;".$_SESSION["labt['$c']"] . "&lt;/td&gt;
            &lt;td&gt;".$_SESSION["Day['$c']"] . "&lt;br/&gt;".$_SESSION["lday['$c']"] . "&lt;/td&gt;
            &lt;td&gt;".$_SESSION["room['$c']"] . "&lt;br/&gt;".$_SESSION["lroom['$c']"] . "&lt;/td&gt;&lt;/tr&gt;&lt;br&gt;";
                 $unit=$_SESSION["lec['$c']"] + $_SESSION["lab['$c']"];
            $c=$c+1;

              $units= $units+$unit;
            }


        }


 echo"&lt;input id='send' name='reset' type='submit' value='reset' /&gt;";
    if(isset($_POST['reset'])){
            unset($_SESSION['name']);
            unset($_SESSION['counter']);
            unset($_SESSION[$_SESSION['counter']]);

        }

 ?&gt;
</code></pre>

<p>thanks in advance</p>
