SELECT проверка по БД

$host='localhost';
$database='csgoxwon';
$user='root';
$password='';
mysqli_connect($host, $user, $password, $database);
$balance = htmlentities(mysqli_real_escape_string($link, $_POST['balance']));
if ($_POST['steamid'] && $_POST['balance']){
$query = mysqli_query("SELECT steamid FROM users WHERE steamid='".mysqli_real_escape_string($_POST['steamid'])."' LIMIT 1");
$data = mysqli_fetch_assoc($query);
if ($data['steamid'] === $_POST['steamid']) {
        echo "<span style='color:blue;'>Баланс обновлен</span>";
}else{
        echo "<span style='color:red;'>SteamID не найден</span>";
 }
}

<p><form method="post">
    <tr>
        <td>&nbsp&nbspSteamID:&nbsp&nbsp</td>
        <td><input type="text" name="steamid" value=""></td>
    </tr>
    <tr>
        <td>&nbsp&nbspБаланс:&nbsp&nbsp</td>
        <td><input type="text" name="balance" size="3" value="">&nbsp&nbsp coins</td>
    </tr>
    <tr>
        &nbsp&nbsp&nbsp <td colspan="2"><input type="submit" value="УСТАНОВИТЬ БАЛАНС"></td>
    </tr>
</form></p>

$host='localhost';
$database='csgoxwon';
$user='root';
$password='';
mysqli_connect($host, $user, $password, $database);
$balance = $_POST['balance'];
$steamid = $_POST['steamid'];
if ($_POST['steamid'] && $_POST['balance']){
$query = mysqli_query("SELECT * FROM `users` WHERE steamid='$steamid' LIMIT 1");
print $steamid;
var_dump($query);
$data = mysqli_fetch_assoc($query);
if ($data['steamid'] === $_POST['steamid']) {
        echo "<span style='color:blue;'>Баланс обновлен</span>";
}else{
        echo "<span style='color:red;'>SteamID не найден</span>";
 }
}

 or die(mysql_error())

or die(mysqli_error())