Group concat ถ้าไม่ได้ใส่ ค่าสามารถให้เป็นค่า null เวลาดึง List ได้ไหมครับ

<?php
//Query SQL
$sql = "SELECT switzer_usermeta.user_id as id,switzer_user_login_log.user_email as email,switzer_user_login_log.time as Time,switzer_user_login_log.ip as Ip,switzer_user_login_log.user_role as role, switzer_usermeta.meta_key , group_concat(COALESCE(switzer_usermeta.meta_value, '') Order by FIELD(switzer_usermeta.meta_key,'first_name','last_name','phone','address','city','state','postcode','ssr_payment_type','ssr_card_expiry_date','ssr_card_last_4_digits','switzer_sale_action','switzer_sale_status','switzer_note_type','wp-last-login') SEPARATOR '|') as fullname 
from switzer_usermeta
JOIN switzer_user_login_log
ON switzer_usermeta.user_id = switzer_user_login_log.uid
where switzer_usermeta.meta_key in('first_name','last_name','phone','address','city','state','postcode','ssr_payment_type','ssr_card_expiry_date','ssr_card_last_4_digits','switzer_sale_action','switzer_sale_status','switzer_note_type','wp-last-login')
group by switzer_usermeta.user_id order by switzer_usermeta.user_id asc";

if(!$result = $db->query($sql)){
    die('There was an error running the query [' . $db->error . ']');
}
?>

//Table
<table width="100%" border="1">
<tr>
<th width="91"> <div align="center">ID </div></th>
<th width="120"> <div align="center">Name </div></th>
<th width="120"> <div align="center">Lastname </div></th>
<th width="198"> <div align="center">Email </div></th>
<th width="198"> <div align="center">Role </div></th>
<th width="198"> <div align="center">Phone </div></th>
<th width="300"> <div align="center">Address </div></th>
<th width="100"> <div align="center">City </div></th>
<th width="100"> <div align="center">State </div></th>
<th width="100"> <div align="center">Postcode </div></th>
<th width="150"> <div align="center">Payment Type </div></th>
<th width="120"> <div align="center">Card Expiry </div></th>
<th width="91"> <div align="center">Card Last 4 Digits </div></th>
<th width="120"> <div align="center">Sale Action </div></th>
<th width="120"> <div align="center">Sale Status </div></th>
<th width="120"> <div align="center">Note Type </div></th>
<th width="130"> <div align="center">Last Logged </div>
<th width="170"> <div align="center">Ip </div>
<th width="91"> <div align="center">Edit </div></th>

//Loop
<?php
while($row = $result->fetch_assoc())


     **///บรรทัดที่ Error เวลาข้อมูลมาไม่ครบอะครับ
list($fname,$lname,$phone,$address,$city,$state,$postcode,$ssr_payment_type,$ssr_card_expiry_date,$ssr_card_last_4_digits,$switzer_sale_action,$switzer_sale_status,$switzer_note_type,$wplast) = explode("|",$row["fullname"]);
?>


<tr>
<td><div align="center"><?=$row['id'];?></div></td><?/*=$objResult["user_id"];*/?>
<td><?=$fname;?></td>
<td><?=$lname;?></td>
<td><?=$row['email'];?></td>
<td><?=$row['role'];?></td>
<td><?=$phone;?></td>
<td><?=$address;?></td>
<td><?=$city;?></td>
<td><?=$state;?></td>
<td><?=$postcode;?></td>
<td><?=$ssr_payment_type;?></td>
<td><?=$ssr_card_expiry_date;?></td>
<td><?=$ssr_card_last_4_digits;?></td>
<td><?=$switzer_sale_action;?></td>
<td><?=$switzer_sale_status;?></td>
<td><?=$switzer_note_type;?></td>
<td><?=$wplast;?></td>
<td><?=$row['Ip'];?></td>
<td><div align="center"><a href="edit.php?edit_id=<?=$row['id'];?>"> Edit</a></div></td><?/*=$objResult["user_id"];*/?>
</tr>
<?php

}
?>
</table>