PHP Mysqli สอบถามการ JOIN TABLE ร่วมกับการ Search ครับ

<?php

   $serverName = "localhost";
   $userName = "root";
   $userPassword = "1234567890";
   $dbName = "ppd";

   $conn = mysqli_connect($serverName,$userName,$userPassword,$dbName);
 $sql = "SELECT a.*,b.* FROM a,b WHERE a.id = b.id ";
 $query = mysqli_query($conn,$sql);

?>
<table width="600" border="1">
  <tr>
	<th width="91"> <div align="center">ลำดับ</div></th>
    <th width="98"> <div align="center">รหัส</div></th>
	  <th width="98"> <div align="center">เลข PO</div></th>
    <th width="198"> <div align="center">ชื่อ</div></th>
    <th width="97"> <div align="center">ผู้ใช้งาน</div></th>
    <th width="59"> <div align="center">ที่เก็บ</div></th>
</tr>
<?php
	
while($result = mysqli_fetch_array($query,MYSQLI_ASSOC))
{
?>
  <tr>
    <td><div align="center"><?php echo $result["id"];?></div></td>
	  <td><?php echo $result["code"];?></td>
    <td><?php echo $result["b_po"];?></td>
    <td><?php echo $result["name"];?></td>
    <td><div align="center"><?php echo $result["b_user"];?></div></td>
    <td align="right"><?php echo $result["location"];?></td>
  </tr>
<?php
}
?>
</table>
<?php
mysqli_close($conn);
?>