View data from database tp pdf using fpdf

Question

I want to view this to pdf file using this code below. I only downloaded it and edit it a little. There's this error stated that: Warning: mysql_fetch_array() expects parameter 1 to be resource, object given in C:\wamp64\www\OFES\Department.php on line 77. FPDF error: Some data has already been output, can't send PDF file

I dont know what is the with the code.Please help me

   <?php
 
require('fpdf/fpdf.php');

class PDF extends FPDF
{
//Page header
function Header()
{
        $pdf = new PDF();
        $pdf->Cell(55, 10, "Comment", 1, 0, "L", 1); 

}

//Page footer
function Footer()
{
        //Position at 1.5 cm from bottom
        $this->SetY(-15);
        //Arial italic 8
        $this->SetFont('Arial','I',8);
        //Page number
        $this->Cell(0,10,'Page '.$this->PageNo().'/{nb}',0,0,'C');
}
}
 
 
        $pdf = new PDF();
        $pdf->open();
        $pdf->AddPage();
        $pdf->AliasNbPages();   // necessary for x of y page numbers to appear in document
        $pdf->SetAutoPageBreak(true);

        // document properties
        $pdf->SetAuthor('INSERT AUTHOR');
        $pdf->SetTitle('INSERT DOC TITLE');

        $pdf->SetFont('Arial','B',14);
        $pdf->Cell(40,10,'                        TITLE FOR REPORT');

        // Add date report ran
        $pdf->SetFont('Arial','I',10);
        $date =  date("F j, Y");
        $pdf->Cell(40,30,'Report date: '.$date);

        $pdf->SetDrawColor(0, 0, 0); //black

        //table header
        $pdf->SetFillColor(170, 170, 170); //gray
        $pdf->setFont("Arial","B","9");
        $pdf->setXY(10, 40); 
        $pdf->Cell(40, 10, "Facutly Name", 1, 0, "L", 1);   // CHANGE THESE TO REPRESENT YOUR FIELDS
        $pdf->Cell(18, 10, "Department", 1, 0, "L", 1);
        $pdf->Cell(25, 10, "Pr", 1, 0, "L", 1);
        $pdf->Cell(30, 10, "AR", 1, 0, "L", 1); 
        $pdf->Cell(55, 10, "IR", 1, 0, "L", 1); 
        $pdf->Cell(55, 10, "PET", 1, 0, "L", 1); 
        $pdf->Cell(55, 10, "CMO", 1, 0, "L", 1); 
        $pdf->Cell(55, 10, "OI", 1, 0, "L", 1); 
        $pdf->Cell(55, 10, "II", 1, 0, "L", 1); 
        $pdf->Cell(55, 10, "MSP", 1, 0, "L", 1); 
        $pdf->Cell(55, 10, "Overall", 1, 0, "L", 1); 

        $y = 50;
        $x = 10;  

        $pdf->setXY($x, $y);

        $pdf->setFont("Arial","","9");

        require('getindividualreports.php');

        $sql = "SELECT * FROM tbl_formative_department_final"; 
        $result = mysqli_query($con,$sql) or die(mysql_error());


while($row = mysql_fetch_array($result))
{
        $pdf->Cell(40, 8, $row['faculty_name'], 1);   
        $pdf->Cell(18, 8, $row['Department'], 1);
        $pdf->Cell(25, 8, $row['PR'], 1);
        $pdf->Cell(30, 8, $row['AR'], 1);
        $pdf->Cell(55, 8, $row['IR'], 1);
        $pdf->Cell(55, 8, $row['PET'], 1);
        $pdf->Cell(55, 8, $row['CMO'], 1);
        $pdf->Cell(55, 8, $row['OI'], 1);
        $pdf->Cell(55, 8, $row['II'], 1);
        $pdf->Cell(55, 8, $row['MSP'], 1);
        $pdf->Cell(55, 8, $row['Overall'], 1);
        $y += 8;

        if ($y > 260)    // When you need a page break
        {
            $pdf->AddPage();
            $y = 40;

        }

        $pdf->setXY($x, $y);
}
 
$pdf->Output();
?>

.