ทำไม อัพเดทข้อมูล ใน access ค่าไม่ตรงกับ ที่ update ไปคะ งงตั้งแต่เมื่อวานแล้ว ¬>¬<

function DateDiff($TODAY,$NET_DUE_DATE){
	$EX_NET_DUE_DATE_BLANK = explode(" ",$NET_DUE_DATE);
	$EX_NET_DUE_DATE = explode("-",$EX_NET_DUE_DATE_BLANK[0]);
	$aNET_DUE_DATE = array($EX_NET_DUE_DATE[0], $EX_NET_DUE_DATE[1], $EX_NET_DUE_DATE[2]);
	$NET_DUE_DATE = implode("-", $aNET_DUE_DATE); //2009-07-31
	$OVERDUE = (strtotime($NET_DUE_DATE)-strtotime($TODAY))/86400;  // 1 day = 60*60*24
	if($OVERDUE<0){
		$OVERDUE = ceil(abs($OVERDUE));
		$OVERDUE = intval("-$OVERDUE");
	}
	else{
		$OVERDUE = ceil($OVERDUE);
		$OVERDUE = intval("+$OVERDUE");
	}
	return $OVERDUE;	
}

#Change DATE 2009-07-31 00:00:00 To 31/07/2009 Same DataType In ACCESS
function ChangeTypeDate($DATA_DATE){
	$EX_DATE_BLANK = explode(" ",$DATA_DATE);
	list($y, $m, $d) = explode('-', $EX_DATE_BLANK[0]);
	$MK_DATE = mktime(0, 0, 0, $m, $d, $y);
	$RESULT_cDATE = strftime('%d/%m/%Y',$MK_DATE);
	return $RESULT_cDATE;
}

$sSql_select = "SELECT *
FROM COMMERCIAL_INV,DATE_SAP
WHERE COMMERCIAL_INV.COMMERCIAL_INV=DATE_SAP.COMMERCIAL_INV;";

$itemresult = odbc_exec($link,$sSql_select);

while($itemrow = odbc_fetch_array($itemresult)){
	$COM_INV = $itemrow['COMMERCIAL_INV'];
	$NET_DUE_DATE = $itemrow['NET_DUE_DATE'];
	$DOC_DATE = $itemrow['DOC_DATE'];
	$TODAY = date("Y-m-d");
	echo "COM_INV : $COM_INV , NET_DUE_DATE : $NET_DUE_DATE , DOC_DATE : $DOC_DATE , TODAY : $TODAY <br/>";
	//COM_INV : 4750028977 , NET_DUE_DATE : 2009-07-31 00:00:00 , DOC_DATE : 2009-07-31 00:00:00 , TODAY : 2010-07-23 
	$OVERDUE = DateDiff($TODAY,$NET_DUE_DATE); //-357
	$NET_DUE_DATE = ChangeTypeDate($NET_DUE_DATE); //NET_DUE_DATE : 31/07/2009
	$DOC_DATE = ChangeTypeDate($DOC_DATE); //DOC_DATE : 31/07/2009
	
	$sSql_update = "UPDATE COMMERCIAL_INV
	SET NET_DUE_DATE = '$NET_DUE_DATE',DOC_DATE = '$DOC_DATE',OVERDUE=$OVERDUE
	WHERE COMMERCIAL_INV = $COM_INV;";
	
	echo $sSql_update . "<br/><br/>";
	
	if(@odbc_exec($link,$sSql_update)){
		echo "update successful<BR/>";
	}
	else{
		echo "update unsuccessful<BR/>";
	}

}
echo "Update Finish.";