title: Query doesn't seem to work
body: <p>I have a login form that asks for a username, a password and a file that contains a key string.
  I want to compare the key in this file with the key on my database and if everything matches, the user logins.
  The problem is that this query doesn't seem to work:</p>
  
  <pre><code>$userBusca = mysqli_query($conn, "SELECT * FROM account.login_admin WHERE login='".$login."' AND password='".$password."' AND key='".$key."'") or die(mysql_error());
  if($userBusca-&gt;num_rows == 1) {
  </code></pre>
  
  <p>It shows me this error, but my mysqli connection is working:</p>
  
  <p>Warning: mysqli_connect() expects parameter 1 to be string, object given in D:\xampp\htdocs\admin\auth\login.php on line 3</p>
  
  <p>this is my line 3:</p>
  
  <pre><code>$dbcon = mysqli_connect($conn, "5.xx.xx.xxx","user","xxxxxx");
  </code></pre>
  
  <p>I'm getting the content of the user file with this:</p>
  
  <pre><code>$file = $_FILES['file'];
  $file_name = $file['name'];
  $file_tmp = $file['tmp_name'];
  $file_size = $file['size'];
  $file_error = $file['error'];
  //whitelist
  $file_ext = explode('.', $file_name);
  $file_ext = strtolower(end($file_ext));
  $allowed = array('txt', 'cfg');
  if(in_array($file_ext, $allowed)) {
  if ($file_error === 0) {
      if($file_size &lt;= 2097152) {
          $file_name_new = uniqid('', true) . '.' . $file_ext;
          $file_destination = 'uploads/' . $file_name_new;
          if(move_uploaded_file($file_tmp, $file_destination)) {
              $key_read_file = $file_destination;
              $key_load = file_get_contents($key_read_file);
              $key = $key_load;
              echo $key;
  </code></pre>
  
  <p>the echo returns the correct result that I want, but for some reason that error keeps popping up.</p>
  
  <p>Thanks in advance</p>