mysqli_result类的对象无法在php的第130行中转换为int

Question

以前我使用的是mysql，所以我迁移到mysqli，并且除向用户发出通知外，其他所有东西似乎都可以正常工作，我使用的是以下代码，并且返回的是mysqli_result类的对象无法在线转换为int

$count_notidwt = mysqli_num_rows($get_notidwt);

这是我的代码

<?php 
                                //getting post comment
                                $get_notipost = mysqli_query($conn,"SELECT * FROM post_comments WHERE posted_to='$user' AND posted_by != '$user' ORDER BY id DESC LIMIT 50");
                                $count_notipost = mysqli_num_rows($get_notipost);
                                //getting daowat comment
                                $get_notidwt = mysqli_query($conn,"SELECT * FROM daowat_comments WHERE daowat_to='$user' AND daowat_by != '$user' ORDER BY id DESC LIMIT 50");
                                $count_notidwt = mysqli_num_rows($get_notidwt);
                                $count = $count_notidwt + $get_notidwt;
                                if ($count != 0) {
                                    //getting daowat noti
                                    while ($noti_dwt = mysqli_fetch_assoc($get_notidwt)) {
                                        $daowat_id = $noti_dwt['daowat_id'];
                                        $daowat_body = $noti_dwt['daowat_body'];
                                        $time = $noti_dwt['time'];
                                        $user_by = $noti_dwt['daowat_by'];
                                        $user_to = $noti_dwt['daowat_to'];
                                        $get_user_info = mysqli_query($conn,"SELECT * FROM users WHERE username='$user_by'");
                                        $get_info = mysqli_fetch_assoc($get_user_info);
                                        $profile_pic_db= $get_info['profile_pic'];
                                        $posted_by = $get_info['first_name'];
                                        ?>

感谢您的帮助。谢谢。