File Explorer

<?php include("db_config.php"); 
if($_SERVER['REQUEST_METHOD']=='POST'){
$user_id = $_POST['user_id'];		
$usersList_array =array();  
$row_array = array();
$note_array = array();
if(!empty($_POST['exam_id'])){
$exam_id=$_POST['exam_id'];
$query_sql = mysqli_query($conn,"SELECT exam_detail.* from exam_detail where id='$exam_id'");
}else{
$query_sql = mysqli_query($conn,"SELECT exam_detail.* from exam_detail "); 
}
while($row_yr = mysqli_fetch_array($query_sql)){
if($row_yr['status'] == "Current"){ $status='Current';
}else{
$status='past';
} }
$sql="SELECT report_detail.*,exam_detail.ex_name,session_year.year,session_year.month from report_detail join student on report_detail.student_id=student.id join exam_detail on report_detail.exam_id=exam_detail.id join session_year on exam_detail.year_id=session_year.id WHERE report_detail.student_id = '".$user_id."' and exam_detail.status = '".$status."'";
$result = mysqli_query($conn, $sql);
$json_response = array();
if(mysqli_num_rows($result) > 0) {
while($row = mysqli_fetch_assoc($result)) {
$row_array['month'] = $row['month'];        
$row_array['ex_name'] = $row['ex_name'];           
$row_array['exam_id'] = $row['exam_id'];
$row_array['notes'] = array();
$exam_id = $row['exam_id'];
$status="1";
$sqllt="SELECT * from subject ";
$exelt=mysqli_query($conn,$sqllt);
while ($reslt=mysqli_fetch_array($exelt)){
$sid=$reslt['id'];
$sql_prdd="SELECT student_marks.*,report_detail.exam_id from student_marks join report_detail on student_marks.report_id=report_detail.id  where student_marks.subject_id='$sid' and report_detail.student_id='$user_id' and report_detail.exam_id='$exam_id' ";
$result_prdd = mysqli_query($conn, $sql_prdd);                            
while($rows = mysqli_fetch_assoc($result_prdd)){
$note_array['id'] = $rows['id'];
$note_array['meter_fas'] = $rows['meter_fas'];
$note_array['meter_fas2'] = $rows['meter_fas2'];
$note_array['meter_fas3'] = $rows['meter_fas3'];
$note_array['meter_fas4'] = $rows['meter_fas4'];
$note_array['t20'] = $rows['t20'];
$note_array['fa_marks'] = $rows['fa_marks'];
$note_array['sa_marks'] = $rows['sa_marks'];
$note_array['total_marks'] = $rows['total_marks'];
$note_array['grade'] = $rows['grade'];
$note_array['grade_point'] = $rows['grade_point'];
array_push($row_array['notes'],$note_array);
} }
array_push($usersList_array, $row_array);
}
}
echo json_encode($usersList_array, JSON_PRETTY_PRINT);
//echo json_encode($response);
mysqli_close($conn);
} ?>

Editing File: report-card.php