get_result在应该返回false时不返回false

The query is executing normally for a successful database search, but for an unsuccessful search it is still following the successful execution path. Is there a different way to analyze $result for an unsuccessful Mysql database query?

$query = "SELECT password
                FROM consumer
                WHERE username = ? ";

            //prepare query
        if ($stmt = $this->conn->prepare($query)) {
            $stmt->bind_param('s', $username);
            $stmt->execute();


            $result = $stmt->get_result();

            if (!is_null($result) && empty($stmt->last_error) && count($result)>0) {

               //successful query, going to this every time even when there
               //is no row in the database that matches the query

            } else {

               //unsuccessful query 
            }

Using count() almost gets you there, except for one small problem. Even if there is no matching password, a single result is still returned, hence count will not return zero. Instead, you can try using mysqli_num_rows, which returns the number of records affected by query. In the case of an empty result set, this should return 0, hence the following check should work:

$rowcount = mysqli_num_rows($result);
if ($rowcount == 0) {
    // unsuccessful query
}