ประกาศตัวแปร array แล้วให้ลิ้งค์ไปยังไฟล์ แต่ข้อมูลไม่แสดง ช่วยทีค่ะ

$columns = array( 

	0 =>'la_name', 
	1 => 'la_no',
	2=> 'la_option'
);


$sql = "SELECT la_name, la_no, la_option ";
$sql.=" FROM books";
$query=mysqli_query($conn, $sql) or die("employee-grid-data.php: get books");
$totalData = mysqli_num_rows($query);
$totalFiltered = $totalData; 


$sql = "SELECT la_name, la_no, la_option ";
$sql.=" FROM books WHERE 1=1'";
if( !empty($requestData['search']['value']) ) {  
	$sql.=" AND ( la_name LIKE '%".$requestData['search']['value']."%' ";    
	$sql.=" OR la_no LIKE '%".$requestData['search']['value']."%' ";
	$sql.=" OR la_option LIKE '%".$requestData['search']['value']."%' )";
}
$query=mysqli_query($conn, $sql) or die("employee-grid-data.php: get books");
$totalFiltered = mysqli_num_rows($query); 
$sql.=" ORDER BY ". $columns[$requestData['order'][0]['column']]."   ".$requestData['order'][0]['dir']."  LIMIT ".$requestData['start']." ,".$requestData['length']."   ";   
	
$query=mysqli_query($conn, $sql) or die("employee-grid-data.php: get books");

 $data = array();
while( $row=mysqli_fetch_array($query) ) {  
    
     $nestedData=array(); 

        
 $nestedData[] = "<a href='file/" .$row["la_file"]. " ' >" .$row["la_name"]."</a>";  // ใส่ลิ้งค์แล้ว มันไม่แสดงข้อมูลเลยค่ะ
	$nestedData[] = $row["la_no"];
	$nestedData[] = $row["la_option"];
	
	$data[] = $nestedData; 
} 



$json_data = array(
			"draw"            => intval( $requestData['draw'] ),    
			"recordsTotal"    => intval( $totalData ), 
			"recordsFiltered" => intval( $totalFiltered ),
			"data"            => $data   
			);

echo json_encode($json_data);