How to check if a row exists compared to another value

//Mysql
$res = mysql_query("YOUR QUERY");
if(mysql_num_rows($res) > 0) {
   $errors[] = "Exists.";
}

//PDO
$query = $db->prepare("YOUR QUERY");
$ret = $query->execute();
if($ret && $query->rowCount() > 0) {
   $errors[] = "Exists.";
}

for this query as

$query=mysql_query("SELECT *  from table WHERE userid = 1 AND badgeid = 1");

and in php

if(mysql_num_rows($query)>0){

// whatever you want if match found 

}else{

echo "No match Found".

}

$sql = "SELECT COUNT(*) FROM `table_name` WHERE `user_id` = '1' AND `badge_id` = '1' "
$exists = mysql_query($sql) ; 
if(mysql_num_rows($exists) >= 1) {
      $errors[] = "Exists.";
}else {
   // doesn't exists.
}

Try using PDO instead of the old mysql_query() functions for they are deprecated since PHP 5.5.

For a simple query:

$slcBadge = $con->query('SELECT badge_id FROM badges');
if ($slcBadge->rowCount() > 0) {
  $errors[] = 'Exists.';
}

Or if you want to fetch all rows from a single user:

$sqlBadge = 'SELECT id_badge FROM badges WHERE id_user = :idUser';
$slcBadge = $con->prepare($sqlBadge);
$slcBadge->bindParam(':idUser', $idUser, PDO::PARAM_INT);
$slcBadge->execute();
if ($slcBadge->rowCount() > 0) {
  $errors[] = 'Exists.';
}

Notice that in the second piece of code I used prepare() and execute() rather than query(). This is to protect you query from SQL injection. By using prepare() you fix the construct of your query so if a user enters a query string as a value, it will not be executed. You only need to prepare a query if a user can enter a value which will be used in your query, otherwise query() will do just fine. Check out the injection link for more detailed info.

Your version of PHP is important:

• mysql_* functions are deprecated as of 5.4, and
• Removed as of 5.5

It is advised to either implement PDO or Mysqli

mysql: This extension is now deprecated, and deprecation warnings will be generated when connections are established to databases via mysql_connect(), mysql_pconnect(), or through implicit connection: use MySQLi or PDO_MySQL instead Dropped support for LOAD DATA LOCAL INFILE handlers when using libmysql. Known for stability problems Added support for SHA256 authentication available with MySQL 5.6.6+

For reference please see the changelog

Structuring your Query

First of all I'm assuming you are indexing your fields correctly refer to this article I posted on Stack Exchange.

Second of all you need to consider efficiency depending on the volume of this table: doing a SELECT * is bad practice when you only need to count the records - mysql will cache row counts and make your SELECT Count(*) much faster. with indexes this is furthermore efficient.

I would simply consider something along the line of this:

$dsn = 'mysql:host=127.0.0.1;dbname=DATABASE';
$db = new PDO($dsn, 'username', 'password', array(
    PDO::MYSQL_ATTR_INIT_COMMAND => 'SET NAMES \'UTF8\''
));

NOTE: where host=127.0.0.1 if your user has been granted access via localhost then you need this to state localhost - or grant the user privileges to 127.0.0.1

NOTE: with SET NAMES there is also a bug with the PDO driver from 5.3 (I believe) whereby an attacker can inject nullbytes and backspace bytes to remove slashing to then inject the query.

##Quick example:

// WARNING: you still need to correctly sanitize your user input!
$query = $db->prepare('SELECT COUNT(*) FROM table WHERE user_id = ? AND badge_id = ?');
$query->execute(array((int) $userId, (int) $badgeId));

$total = $query->fetchAll();

$result = mysql_query("SELECT COUNT(*) FROM table WHERE userid = 1 AND badgeid = 1 LIMIT 1") or die(mysql_error());
if (mysql_result($result, 0) > 0)
{
   echo 'exist';
}
else
{
   echo 'no';
}