multi select box selected

[lien]

i have two tables

staff

stid, staff
1| lien
2| tony
3| tom
4| henry

bill

billid, stid

1| 1,3

i need for it to display all the staff from the staff table in a multiselect box then have the staff in the bill table selected.
i can't figure out how to do this.
this code below currently only displays the staff table. any help would be appreciated.

<tr>
<td width="10%" align="right"><div class="label">Staff</div></td>
<td>

<SELECT name='stid[]' class="one_pixel_border" size=5 multiple>
<?
$sQuery = mysql_query("SELECT stid, staff FROM staff");
while ($sRow = mysql_fetch_row($sQuery))
{

if( $stid == $sRow[0] ) {
print ("<OPTION SELECTED value='$sRow[0]'>$sRow[1]</OPTION>");
} else {
print ("<OPTION value='$sRow[0]'>$sRow[1]</OPTION>");
} // end of conditions
} // end of while loop

?></SELECT>

     </td>
  </tr>

[leatherback]

Hi,

first off: Please place code in tags for clearer reading (See the pretty colors below).

Have a look at this:

// assuming you do something like:
$stid = $_GET['stid']

$sQuery = mysql_query("SELECT stid, staff FROM staff");
while ($sRow = mysql_fetch_row($sQuery))
  {
  if(is_array($stid))
    {
    if(array_key_exists($sRow['stid'], $stid))
      {
       echo "<OPTION SELECTED value='$sRow[0]'>$sRow[1]</OPTION>";
      } 
   else 
     {
      echo "<OPTION value='$sRow[0]'>$sRow[1]</OPTION>";
     }
   }
 else
   {
    echo "<OPTION value='$sRow[0]'>$sRow[1]</OPTION>";
  }
} // end of while loop

?>

</td>
</tr>

Please note: I am not sure that the selected keyword works in a multiselect list. I assume you verified that.