$ratequeri="SELECT type FROM roomreservation ORDER BY room_no DESC LIMIT 1 ";
 mysql_select_db($database_ast_conn, $ast_conn);
  $Result111 = mysql_query($ratequeri, $ast_conn) or die(mysql_error());
  $omgg=mysql_fetch_array($Result111);
$rrate;
if($omgg=="Deluxe Floor Room"){$rrate=350;}
elseif($omgg=="Executive Club Floor Room"){$rrate=350;}
elseif($omgg=="Junior Suite"){$rrate=350;}
elseif($omgg=="Executive Suite"){$rrate=350;}
elseif($omgg=="Presidential Suite"){$rrate=350;}


$insertqueri="INSERT INTO roomreservation (rate) VALUES ('$rrate') "; 
 mysql_select_db($database_ast_conn, $ast_conn);
  $Result1111 = mysql_query($insertqueri, $ast_conn) or die(mysql_error());
  /////////////////////////
  this the error i get

  Notice: Undefined variable: rrate in C:\wamp\www\ast_project\bookonline.php on line 87

this the error i get
Notice: Undefined variable: rrate in C:\wamp\www\ast_project\bookonline.php on line 87

plz help me solve it :(
thanking in advance

You are not using the data returned from your query correctly, please note that any results returned are always in an array, therefore your if else statements should be:

if($omgg['type'] == "Deluxe Floor Room"){$rrate=350;}

Or you can assign the returned result to a variable first:

$type = $omgg['type'];
if($type == "Deluxe Floor Room"){$rrate=350;}