Substring in a where clause

Hello all

I have some problemes inserting a substring in a where clause. All the code works xith a simple where= . I am soinf something wring in the substring but i can't find out what. Any help is welcome .
Tks !

<?php 
$cible=$_REQUEST['cible']; 
mysql_connect("xxxxxxxxx", "root", "xxxxxxxxx") or die(mysql_error());
mysql_select_db("xxxxxxxx");
?>

<select name="city" id="city" style="width:auto; margin-right:10px;" onChange="getxxxxxx('xxxxxxxx.php?diagrefs='+this.value)" >    
<?php    
$req = "[B]SELECT * FROM xxxxxxxxxx WHERE SUBSTRING(field_xxxxxxx,0,2)=$cible[/B]";
$result = mysql_query($req);
while($row=mysql_fetch_array($result))
{ 
echo '<option value="'.$row['xxx'].'">'.$row['xxxxxx'].' - '.$row['xxxxx'].' - '.$row['xxxx'].'</option>';      
}    

Code (markup):

?>
</select>

 

$req = "SELECT * FROM xxxxxxxxxx WHERE ".SUBSTRING(field_xxxxxxx,0,2)."=$cible";

 

Hello

Thanks for your answer, i actually got the answer from another forum. My script works if I use ,1,2 in the substring. If i use ,0,2, it comes back empty. This point is actually explained black on white in the documentation. I should have RTFM