query("SELECT * FROM students as s,centers as c WHERE s.id = '".$_SESSION['student']['id']."' and s.center_id = c.id");
if($selectCourses->num_rows){
$student = $selectCourses->fetch_assoc();
$courses = $con->query("SELECT * FROM exams as e WHERE e.course_id = '".$student['course_id']."' and start != 'NULL' and end != 'NULL' and status = '1' ");
if($courses->num_rows){
// echo $courses->num_rows;
while($row = $courses->fetch_assoc()){
$start = strtotime($row['start']);
$end = strtotime($row['end']);
echo '