เกี่ยวกับเรื่อง between ครับ ผมงง ว่าไม่รู้จะใส่ยังไงดี ช่วยหน่อย

if (isset($_POST["insert_meeting"]) &&($_POST["insert_meeting"]=="insert_meeting")) {
	$new_m_name = $_POST['subject'];
	$new_m_president = $_POST['header'];
	$new_m_num_guest = $_POST['nummeeting'];
	//$new_m_date = $_POST['startdate'];
	
	$date_select = split('[/.-]',$_POST[startdate]);
			$show_day = $date_select[1];
			$show_mon = $date_select[0];
			$show_year = $date_select[2];
			$new_m_date = $show_year."-".$show_mon."-".$show_day;
			
	$new_m_room = $_POST['room_id'];
	$new_m_sts = $_POST['starttime'];
	$new_m_ste = $_POST['endtime'];
	$new_m_tool = $_POST['checktool'];
	$u_fullname1 = $row_user['starttime']." ".$row_user['endtime'];
	if(count($new_m_tool) > 0){
			$i=0;
			foreach($new_m_tool as $mt){
				if($i!=0){
					$new_m_toolst = $new_m_toolst.",".$mt;
				}else{
					$new_m_toolst = $new_m_toolst.$mt;
				}
				$i++;
			}
			$new_toolst = $new_m_toolst;
		}
	$new_m_food = $_POST['checkfood'];
	if(count($new_m_food) > 0){
			$i=0;
			foreach($new_m_food as $mf){
				if($i!=0){
					$new_m_foodst = $new_m_foodst.",".$mf;
				}else{
					$new_m_foodst = $new_m_foodst.$mf;
				}
				$i++;
			}
			$new_foodst = $new_m_foodst;
		}
	$new_m_detail = $_POST['comment'];
	$new_m_user = $_SESSION['user'];

$sql = "select * From meeting Where m_room = '".trim($_POST["room_id"])."'";
$objectQuery = mysql_query($sql,$Conn) or die(mysql_error());
$objResult = mysql_fetch_array($objectQuery);
if($objResult){
echo "<script>alert('ห้องประชุมนี้ได้ถูกจองแล้ว')</script>";

}
else{
					$sql = sprintf("INSERT INTO meeting (m_name,m_president,m_num_guest,m_room,m_date,m_sts,m_ste,m_tool,
					m_food,m_detail,m_user,create_date,create_by) VALUES (%s,%s,%s,%s,%s,%s,%s,%s,%s,%s,%s,NOW(),'ADMIN')", 
						GetSQLValueString($new_m_name, "text"),
						GetSQLValueString($new_m_president, "text"),
						GetSQLValueString($new_m_num_guest, "text"),
						GetSQLValueString($new_m_room, "text"),
						GetSQLValueString($new_m_date, "text"),
						GetSQLValueString($new_m_sts, "text"),
						GetSQLValueString($new_m_ste, "text"),
						GetSQLValueString($new_toolst, "text"),
						GetSQLValueString($new_foodst, "text"),
						GetSQLValueString($new_m_detail, "text"),
						GetSQLValueString($new_m_user, "text"));
					mysql_query($sql,$Conn) or die(mysql_error());
	echo "<script>window.location='cancelform.php'</script>";
}
}