จะทำยังให้ให้วันที่มีค่า in - ค่า out ลบด้วยจำนวนรวมของไอดีนะครับ แล้วส่วนวันที่ไม่มีค่า in - out ให้มีค่าเป็น room_total ทั้งหมดนะครับ

<?
$date_in ="2015-05-10";
$date_out ="2015-05-20";

function DateDiff($strDate1,$strDate2)
	 {
				return (strtotime($strDate2) - strtotime($strDate1))/  ( 60 * 60 * 24 ); 
	 }
$datechoose = DateDiff($date_in,$date_out);
for($i=0;$i<=$datechoose;$i++){
$strStartDate = $date_in;
$strNewDate = date ("Y-m-d", strtotime("+$i day", strtotime($strStartDate)));

$objConnect = mysql_connect("localhost","root","1234") or die("Error Connect to Database");
$objDB = mysql_select_db("booking");
mysql_query("SET character_set_results=tis620");
mysql_query("SET character_set_client=tis620");
mysql_query("SET character_set_connection=tis620");
$strSQL = "SELECT id,room_name FROM room_tb";
$objQuery = mysql_query($strSQL) or die ("Error Query [".$strSQL."]");



?>
<table width="600" border="1">
  <tr>
    <th width="91" colspan="2"> <div align="left"><? echo $strNewDate;  ?> </div></th>

  </tr>
<?php
while($objResult = mysql_fetch_array($objQuery))
{
?>
  <tr>
    <td><div align="center"><?php echo $objResult["id"];?>.)    <?php echo $objResult["room_name"];?> </div></td>
    
<?
$room_no = $objResult["id"];//ไอดีห้อง
?>
    
<?
 $sql = mysql_query("select booking.chk_in_date,booking.chk_out_date,booking.booking_id,booking_room.booking_id,booking_room.room_id,room_tb.id,room_tb.room_total 
from booking 
INNER join booking_room 
on booking.booking_id = booking_room.booking_id
inner join room_tb
on booking_room.room_id = room_tb.id
WHERE booking_room.room_id = $room_no 
");
$records = mysql_num_rows($sql);
$info = mysql_fetch_array( $sql);
$totalroom = $info['room_total'] ;
$amount  = $totalroom - $records;
?>
<td><?  echo  $amount;   ?>  </td></tr>
<?php
}
?>
</table>
<?php
mysql_close($objConnect);
}
 ?>