Bind the selected values to the checkbox in php

I have a php code snippet mentioned below

 <?php  $query = "SELECT * FROM Qualification";
    $result = mysqli_query($dbcon,$query);
    while($row=mysqli_fetch_array($result)){ 
   ?>   
<input type='checkbox' value='"<?php $row['Id'] ?> "' name='Qualification[]' /><?php  $row['Description'] ?><br>

<?php } ?>

This above Code is used to Display all the qualification from the databases .

Output will be

[] Teacher
[] Engineer
[] Doctor
[] Banker etc..

Now say i have checked 3 checkboxes Teacher,Engineer,Doctor.

foreach($_POST['Qualification'] as $Qualification) 
         {
            $AllQualification .=$Qualification.",";
         }

$AllQualification ="1,2,3,"

So i am concatenating the ID of the values into a string and store it in database as 1,2,3,

Now i need to bind the datas again to that checkbox. When i am retriving the selected qualification it gives 1,2,3,

Now How to bind the selectedvalues to the checkbox.

The output i need is teacher,Engineer,Doctor should be checked and banker should be uncheked.

Any help appreciated.