检查用户是否存在

I did a lot of googling and tried many methods but checking for username existence in Mysqli database is not working. Everything is correct but still the user is getting registered even if there is a username in Database. Please help...My php version is 7 and phpmyadmin is 5.6. My code :-

<?php 
session_start();
if (isset($_SESSION['id'])) {
header('Location: user.php');
die();
}

else {
if($_POST['submit']){

    $username = strip_tags($_POST['username']);
    $email = strip_tags($_POST['email']);
    $password = strip_tags($_POST['password']);
    $passhash = hash('sha512', $password);
    $passhash2 = hash('sha512', $passhash);
    $strlen = strlen("$password");
    if ($strlen < 10) {   {
    $lesspass = "Use password of atleast 10 letters";
    }
    }
    else {
    $date = date("Y-m-d");
    require ('setup.php');
    $conn = new mysqli($localhost, $hostuser, $hostpass, $hostdb) or die("conn died");
    $query1 = "SELECT * FROM member WHERE username = '$username'";
    $result1 = mysqli_query($conn, $query1);
    if (mysqli_num_rows($query1) > 0) {
        die ("Username in use");
    }

    else {
    $query2 = "SELECT from member WHERE email = $email";
    $result2 = mysqli_query($conn, $query2);

    if (($result2) > 0)  {
        $ee = "Email already exists";
    }
    else {

    $query = "INSERT INTO member(username, password, registered, email, activated, status) VALUES('$username', '$passhash2', '$date', '$email', '1', '0')";
    $result = mysqli_query($conn, $query);
    if($result) {
        header('Location: login.php');
    }
    else {
        echo "There was a problem while connecting";
    }
    }
}
}
}
}



?>

I think the error is that you use mysqli_num_rows on the query string. Do it on the result:

if (mysqli_num_rows($result1) > 0) {

Also, you should take care about SQL injections (escape or use prepared statements), but that's another story. Not sure if strip_tags is sufficient.