จะนำค่า CONCATENATE ใน Excel เข้า Mysql แต่เข้าเป็นค่าว่าง

Code[/head]
[code] include "../connect.php"; 
 require_once 'Excel/reader.php';
$data = new Spreadsheet_Excel_Reader(); 
$data->setOutputEncoding('UTF-8');
$filename=$_GET[file];
$data->read("file/".$filename);
for ($i = 2; $i <= $data->sheets[0]['numRows']; $i++) {
	for ($j = 1 ; $j <= $data->sheets[0]['numCols']; $j++) {
	"\"".$data->sheets[0]['cells'][$i][$j]."\"";
	$xxx[$i][$j] = iconv("UTF-8","windows-874",$data->sheets[0]['cells'][$i][$j]);
	}
	$str = "SELECT * FROM regis where id_std='{$xxx[$i][1]}' and status_exam='1' ";
	$result5 = mysql_db_query($db, $str);
	if (mysql_num_rows($result5)) {
	$sql2 = "insert into regis (id_std,term,unit_learn,result_fail,status_exam) values ('{$xxx[$i][1]}','$_GET[term]','{$xxx[$i][3]}','{$xxx[$i][3]}','1')";
  	mysql_query($sql2);
}else{
	$sql2 = "insert into regis (id_std,term,unit_learn,result_fail) values ('{$xxx[$i][1]}','$_GET[term]','{$xxx[$i][3]}','{$xxx[$i][3]}')";
	mysql_query($sql2);
	}
	$sql3 = "insert into login (user,pass,id_level) values ('{$xxx[$i][1]}','{$xxx[$i][1]}','5')";
	$sql4 = "insert into student (id_std,name,fac,category) values ('{$xxx[$i][1]}','{$xxx[$i][2]}','{$xxx[$i][4]}','{$xxx[$i][5]}')";
	$sql5 = "insert into advancement_minor (id_std,name_std) values ('{$xxx[$i][1]}','{$xxx[$i][2]}')";
	$sql6 = "insert into relation_teach (id_std) values ('{$xxx[$i][1]}')";
	mysql_query($sql3);
	mysql_query($sql4);
	mysql_query($sql5);
	mysql_query($sql6);
}