Как присоединиться к скрипту count в PHP mysqli

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I have one problem I have added unread count filed to my script After display like this message

Fatal error: Call to a member function get_result() on boolean in C:\xampp\htdocs\demo\npm\cons.php on line 110

I have added line

  (SELECT from_id, COUNT(*) unread FROM pm WHERE to_id=? AND read='0' GROUP BY from_id)


my problem here SELECT from_id, I want to add it counting one by one users unread messages showing i want to know to add it to my script.

my database pm table

    id  from_id     to_id    msg               sent_date              read    
    1   2           3        hi how are you?   2019-12-05 04:14:20    1                
    2   3           2        fine              2019-12-05 05:15:58    0               
    3   2           3        hi                2019-12-05 03:20:34    1                  
    4   5           2        hi                2019-12-05 08:30:40    0   
users table

userid username
2      previn
3      rajesh
5      raj
Here is my source code

    <?php
     if (isset($_SESSION['userid'])) {
        $session_id = $_SESSION['userid'];
     }


    $sql = "SELECT *,

    (SELECT username FROM users WHERE userid=from_id) AS from_username,
    (SELECT username FROM users WHERE userid=to_id) AS to_username,
    (SELECT username FROM users WHERE userid=?) AS my_username,
(SELECT from_id, COUNT(*) unread FROM pm WHERE to_id=? AND read='0' GROUP BY from_id)


    FROM pm WHERE from_id = ? or to_id=?   ORDER BY id DESC";


    if ($stmt->prepare($sql)) {
       $stmt->bind_param('iiii', $session_id, $session_id,$session_id,$session_id);
       $stmt->execute();
       $result = $stmt->get_result();
       while ($row = $result->fetch_assoc()) {
          echo $row['from_username'] . " -> " . $row['to_username'] . "<br>";
          echo 'User ' . $row['from_id'] . ' - ' . $row['unread'];
       }
      }
    ?>

Что я уже пробовал:

&низкотемпературный;

I have added line
<code><pre> (SELECT from_id, COUNT(*) unread FROM pm WHERE to_id=? AND read='0' GROUP BY from_id)

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