php导出excel中，若数据库一列内容中存在换行，则在excel中对应换成多行，如何解决？

<?php //验证是否已登录include 'remember_password.php';	header("Accept-Ranges: bytes");	header("Content-type: application/vnd.ms-excel");	header("Content-Disposition: attachment; filename=".$filename);	include("connect.php");	$sql="select * from specific_step";	$query = mysql_query($sql);	echo "序号\t业务名称\t操作步骤\t备注\t录入人\t录入日期";	while($row = mysql_fetch_array($query)){		echo "\n";		echo $row['serial_number']."\t".$row['name']."\t".$row['step']."\t".$row['other']."\t".$row['input_name'].		"\t".$row['input_date'];	}?>

header("Accept-Ranges: bytes");header("Content-type: application/vnd.ms-excel");header("Content-Disposition: attachment; filename=".@$filename);$ar = array(  "abcd123",  "再来一段换行再换行");echo "序号\t备注\n";foreach($ar as $k=>$v) {  echo "$k\t\"$v\"\n";}

header("Accept-Ranges: bytes");header("Content-type: application/vnd.ms-excel");header("Content-Disposition: attachment; filename=".@$filename);$ar = array(  "abcd123",  "再来一段换行再换行");echo "序号\t备注\n";foreach($ar as $k=>$v) {  echo "$k\t\"$v\"\n";}

header("Accept-Ranges: bytes");header("Content-type: application/vnd.ms-excel");header("Content-Disposition: attachment; filename=".@$filename);$ar = array(  "abcd123",  "再来一段换行再换行");echo "序号\t备注\n";foreach($ar as $k=>$v) {  echo "$k\t\"$v\"\n";}