เช็คดักค่าเวลา ทับกัน ใครบางมีแนวทาง ช่วยหน่อยครับ

$time1 = $_POST['time1'];// '24-8-2555 09.00';
$time2 =  $_POST['time2'];//'24-8-2555 13.00'; 
$clean['time1'] = mysql_real_escape_string($time1);
$clean['time2'] = mysql_real_escape_string($time2);
$query = "select * from booking where (cast('$clean[time1]' as datetime) between time_begin AND time_finish)  or  (cast('$clean[time2]' as datetime) between time_begin AND time_finish)  ";

$rs = mysql_query($query);
if (mysql_num_rows($rs) > 0){
    die('ช่วงเวลานี้ถูกจองไปแล้ว');
}

$time1 = $_POST['time1'];// '24-8-2555 09.00';
$time2 =  $_POST['time2'];//'24-8-2555 13.00'; 
$clean['time1'] = mysql_real_escape_string($time1);
$clean['time2'] = mysql_real_escape_string($time2);
$query = "select * from booking where (cast('$clean[time1]' as datetime) between cast(concat(date_begin,' ',time_begin) as datetime) AND cast(concat(date_finish,' ',time_finish) as datetime)))  or  (cast('$clean[time2]' as datetime) between cast(concat(date_begin,' ',time_begin) as datetime) AND cast(concat(date_finish,' ',time_finish) as datetime))  ";

$rs = mysql_query($query);
if (mysql_num_rows($rs) > 0){
    die('ช่วงเวลานี้ถูกจองไปแล้ว');
}