密码不与MySQLi哈希

I'm currently making a registration form, everything seems to work fine except for the password part. When the user register, the password should be hashed but I still see a normal string in phpmyadmin. I would like to make it when a user input his password, it should be hashed in the database.

Here is my code:

public function reg_user($gender, $username, $email, $password, $firstname, $lastname, $birthday, $city) {
            $sql = "SELECT * FROM users WHERE username='$username' OR email='$email'";  
            password_hash($password, PASSWORD_DEFAULT);
            password_verify($password,$row['password']);
            $check =  $this->db->query($sql);
            $count_row = $check->num_rows;
            if ($count_row == 0) {
                $sql1 = "INSERT INTO users (gender, username, email, password, firstname, lastname, birthday, city) VALUES ('$gender', '$username', '$email', '$password', '$firstname', '$lastname', '$birthday', '$city')";
                $result = mysqli_prepare($this->db,$sql1) or die(mysqli_connect_errno() . " - ERREUR: Les données ne peuvent pas être insérés");
                $password = md5($password, PASSWORD_DEFAULT);
                $result->execute();
            } else {
                return false;
            }
        }

        include_once 'class.user.php';
        $user = new User();
        password_verify($password,$row['password']);
        password_hash($password, PASSWORD_DEFAULT);
        $password = password_hash($password, PASSWORD_DEFAULT);
        if (isset($_POST['submit'])) {
            extract($_POST);
            $register = $user->reg_user($_POST['gender'], $_POST['username'], $_POST['email'], $_POST['password'], $_POST['firstname'], $_POST['lastname'], $_POST['birthday'], $_POST['city']);
            if ($register) {
                echo "<span class=\"waters\">Inscription confirmée</span>";
                password_verify($password,$row['password']);
                password_hash($password, PASSWORD_DEFAULT);
            } else {
                echo "<span class=\"waters\">Inscription confirmée</span>";
                password_verify($password,$row['password']);
                password_hash($password, PASSWORD_DEFAULT);
            }
        }

Thanks for reading.

Change the order of lines: you first generate the SQL query, and afterwards call a hash method for the given password.

Additionally, keep in mind that md5 is not a secure hash function any more