รบกวนช่วยดู code update แบบ วนลูป ให้หน่อยครับ ข้อมูลจะซ้ำกันตลอดเวลา update

<form id="frmSearch" name="frmSearch" method="post" action="update_shift.php" onSubmit="JavaScript:return fncSubmit();">
        <TABLE width="294" border=1 align="center" cellPadding=2 cellSpacing=0 class="body">         
          <TBODY>
          <TR class="body">
            <td height="27" colspan="2" align="center" bgcolor="#8DA5BD">&nbsp;<b>MANAGE SHIFT</b></td>
            </TR>
          <TR class="body">
            <td height="27"><strong>Departure Date :</strong></td>
            <TD ><label for="departuredate"></label>
              <input name="departuredate" type="text" id="departuredate" readonly="readonly" value="<?php echo $date_chack ?>" /></TD>
          </TR>
          <TR class="body">
            <td height="27"><strong>Destination :</strong></td>
            	 <input name="tourID_id" type="hidden" id="tourID_id" readonly="readonly" value="<?php echo $tourID_id ?>" />
            <TD ><input name="tourID" type="text" id="tourID" readonly="readonly" value="<?php echo $destination_name ?>" /></TD>
          </TR>
          
          <?php
		  
			$queryzz2012 = "SELECT * FROM shift_management WHERE tourID = '$destination' and datediff(departuredate,'$departuredate') = 0";
			
			$objQuery = mysql_query($queryzz2012);
			$i = 0;
			$staffID = array();
			$shiftID = array();
			while($objResuut = mysql_fetch_array($objQuery))
			{
			
			$staffID[$i] = $objResuut["staffID"];
			$i++;
            }
			?>
          
          <TR class="body">
            <td height="27"><strong>Captian :</strong></td>
           
            	 <input name="dutyID[]" type="hidden" id="dutyID" value="001" />
            <TD ><input type="text" name="staffID[]" id="staffID" value="<?php echo $staffID[0] ?>" /></TD>
          </TR>
          <TR class="body">
            <td height="27"><strong>Engineer :</strong></td>
            	 <input name="dutyID[]" type="hidden" id="dutyID" value="002" />
            <TD ><input type="text" name="staffID[]" id="staffID" value="<?php echo $staffID[1] ?>" /></TD>
          </TR>
          <TR class="body">
            <td height="27"><strong>Crew I :</strong></td>
            	 <input name="dutyID[]" type="hidden" id="dutyID" value="003" />
            <TD ><input type="text" name="staffID[]" id="staffID" value="<?php echo $staffID[2] ?>"/></TD>
          </TR>
          <TR class="body">
            <td height="27"><strong>Crew II :</strong></td>
            	 <input name="dutyID[]" type="hidden" id="dutyID" value="004" />
            <TD ><input type="text" name="staffID[]" id="staffID" value="<?php echo $staffID[3] ?>"/></TD>
          </TR>
          <TR class="body">
            <td height="27"><strong>Guide Leader :</strong></td>
                 <input name="dutyID[]" type="hidden" id="dutyID" value="005" />
            <TD ><input type="text" name="staffID[]" id="staffID" value="<?php echo $staffID[4] ?>"/></TD>
          </TR>
          <TR class="body">
            <td height="27"><strong>Guide :</strong></td>
                 <input name="dutyID[]" type="hidden" id="dutyID" value="006" />
            <TD ><input type="text" name="staffID[]" id="staffID" value="<?php echo $staffID[5] ?>"/></TD>
          </TR>
          <TR class="body">
            <td height="27"><strong>Photographer :</strong></td>
            	 <input name="dutyID[]" type="hidden" id="dutyID" value="007" />
            <TD ><input type="text" name="staffID[]" id="staffID" value="<?php echo $staffID[6] ?>"/></TD>
          </TR>
          <TR class="body"> 
            <td width="116" height="27"><strong>Video :</strong></td>
            				 <input name="dutyID[]" type="hidden" id="dutyID" value="008" />
            <TD width="164" ><input type="text" name="staffID[]" id="staffID" value="<?php echo $staffID[7] ?>"/></TD>
            </TR>
        </TBODY>
    </TABLE>
    <p>
    <input type="submit" name="button" id="button" value="Submit Form" />&nbsp;
		<input type="reset" name="button2" id="button2" value="Reset Form" />
    </form>

<?php
require('conn_mysql.php');

for($i=0;$i<count($_POST["staffID"]);$i++)
{
$date_go = $_POST['departuredate'];
$tourID_id = $_POST['tourID_id'];
$staffID = $_POST['staffID'][$i];
$dutyID = $_POST['dutyID'][$i];

$sql3 = "update shift_management set departuredate='$date_go',tourID='$tourID_id',staffID='$staffID',dutyID='$dutyID' WHERE tourID='$tourID_id' and departuredate='$date_go'";
echo $sql3;
$query = mysql_query($sql3) or die(mysql_error());

			
}
?>