找到一个值大于或等于给定数字的行（mysql）

Question

I'm creating a rank system and ranks are stored in a database, my problem is about finding rows with greater or equal value to given user xp:

It's something like this:

list of ranks in ranks table:

name: Rank1 exp: 400

name: Rank2 exp: 500

name: Rank3 exp: 700

$xp = "500";

$find = $db->query("SELECT * FROM ranks WHERE exp >= '$xp' LIMIT 1");

if($find->num_rows > 0){
 // if a rank with greater than or equal value was found
  $rdata = $find->fetch_assoc();
 // return rank name
  echo $rdata["name"];
}

this returns Rank1, i don't know why :(

Can anyone help me? I'm not yet good in mysql.

Answer 1

Remove the " " around 500, but for future reference I'd turn this into a prepared statement as your query isn't as secure as it could be

$xp = 500;

$query = "SELECT name FROM ranks WHERE exp >= ?' LIMIT 1";
$stmt = $db->prepare($query);
$stmt->bind_param("s",$xp);
$stmt->execute();
$stmt->bind_param($name);
while($stmt->fetch()){
   if($stmt->num_rows > 0 ){
      echo $name;
    }
}

Another suggestion. Instead of selecting where >= $xp and limiting by 1, Why not select the range you're actually looking for? between 500 and 700 so it doesn't bring back 700?