cara menghapus sebagian data di php ?

agan mau bikin laporan pake fpdf tampilin jg kodingannya

itu om coding nya diatas ada, kalau mau lengkap ini saya kasih :

<?php
//koneksi ke database
include "koneksi.php";
//$id_admin=$_SESSION['session_id'];
$id_user = $_GET['id_user'];
if(isset($id_user)){
//mengambil data dari tabel jika $id_user ada.
$sql=mysqli_query($koneksi,"SELECT * FROM data WHERE id_user = '$id_user'");
}
else{
//mengambil data dari tabel jika $id_user tidak ada.
$sql=mysqli_query($koneksi,"SELECT * FROM data");
}
$data = array();
while ($row = mysqli_fetch_assoc($sql)) {
    array_push($data, $row);
}


//mengisi judul dan header tabel
$judul = "Tabel Pengukuran ";
$header = array(
array("label"=>"no", "length"=>5, "align"=>"L"),
array("label"=>"id_user", "length"=>13, "align"=>"L"),
array("label"=>"Time", "length"=>17, "align"=>"L"),
array("label"=>"Date", "length"=>17, "align"=>"L"),
array("label"=>"lat", "length"=>19, "align"=>"L"),
array("label"=>"longi", "length"=>20, "align"=>"L"),
array("label"=>"Altitude", "length"=>20, "align"=>"L"),
array("label"=>"Suhu", "length"=>10, "align"=>"L"),
array("label"=>"Humidity", "length"=>16, "align"=>"L"),
array("label"=>"Roll", "length"=>10, "align"=>"L"),
array("label"=>"Pitch", "length"=>10, "align"=>"L"),
array("label"=>"K_Tanah", "length"=>17, "align"=>"L"),
array("label"=>"pH_Tanah", "length"=>19, "align"=>"L"),
array("label"=>"luas", "length"=>17, "align"=>"L"),
array("label"=>"keliling", "length"=>13, "align"=>"L"),
array("label"=>"Ket", "length"=>23, "align"=>"L"),
array("label"=>"File_name", "length"=>40, "align"=>"L"),
);

//memanggil fpdf
require_once ("fpdf.php");
$pdf = new FPDF();
$pdf->AddPage('L','A4');

//tampilan Judul Laporan
$pdf->SetFont('Arial','B','16'); //Font Arial, Tebal/Bold, ukuran font 16
$pdf->Cell(0,20, $judul, '0', 1, 'C');

//Header Table
$pdf->SetFont('Arial','','10');
$pdf->SetFillColor(139, 69, 19); //warna dalam kolom header
$pdf->SetTextColor(255); //warna tulisan putih
$pdf->SetDrawColor(222, 184, 135); //warna border
foreach ($header as $kolom) {
    $pdf->Cell($kolom['length'], 5, $kolom['label'], 1, '0', $kolom['align'], true);
    }
$pdf->Ln();

//menampilkan data table
$pdf->SetFillColor(245, 222, 179); //warna dalam kolom data
$pdf->SetTextColor(0); //warna tulisan hitam
$pdf->SetFont('');
$fill=false;
foreach ($data as $baris) {
$i = 0;
foreach ($baris as $cell) {
$pdf->Cell($header[$i]['length'], 5, $cell, 1, '0', $kolom['align'], $fill);
$i++;
}

$fill = !$fill;
$pdf->Ln();
}

//output file pdf
$pdf->Output();
?>