error mysql_fecth_assoc

[T4ke0veR]

me dice esto

You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near '' at line 1

Código PHP:

  <?php     
include ('conect.php');    
 
$sqlex="SELECT `email`, COUNT(*) AS 'total', SUM(`monto`) AS 'suma' FROM `factura` GROUP BY `email`";    
$sql_execex=mysql_query($sqlex);   
while($rowex=mysql_fetch_assoc($sql_execex))    
{     
?>  
<?php   
$sqlexz="SELECT * FROM clientes WHERE email=".$rowex['email'];  
$sql_execexz=mysql_query($sqlexz) or die(mysql_error());   
while($rowexz=mysql_fetch_assoc($sql_execexz)) {  
?>   
 
<table width="955" border="0" cellspacing="0" cellpadding="0">    
  <tr>    
    <td><table width="200" border="1" bgcolor="#999999">    
 
       
 
      <tr>    
        <td width="80" bgcolor="#FFFFFF"><?php echo $rowex['suma']; ?></td>    
          <td width="80" bgcolor="#FFFFFF"><?php echo $rowex['total']; ?></td>    
          <td width="40" bgcolor="#FFFFFF"><?php echo $rowexz['email']; ?></td>    
        </tr><?php }?>   
        <?php }?>        
      </table>    
      <p>&nbsp;</p>  
    <p>&nbsp;</p></td>    
  </tr>