PHP - Mysqli - Can Someone Cast An Eye Over These Statements?

<?php
MAKING CONNECTION

if ($stmt = $mysqli->prepare("SELECT year FROM SOMETABLE WHERE id = ? LIMIT 1")) {

    $id = $_GET['id'];
    
    $stmt->bind_param("i", $id);
    
    
    $stmt->execute();
    
    
    $stmt->bind_result($year);
    
    $stmt->fetch();
    
    echo $year;
        
    
    $stmt->close();
}
$mysqli->close();

?>

Hi !

I am trying to translate my mysqli count query that works perfectly into prepared statements.

Unfortunately, after playing around and using my knowledge of PS, I have come up with this script which fails to execute and returns a http 500 error.

I may have missed something very silly, I require some guidance on fixing the error.

<?php


$conn = mysqli_connect("xxxx", "xxxx", "xxxx", "xxx");

$sel_query = "SELECT 
    S1, B1
    COUNT(IF(S1 = ?, 1, NULL)) 'Accepted',
    COUNT(IF(S1 = ?, 1, NULL)) 'Rejected',
    COUNT(IF(S1 = ?, 1, NULL)) 'Under_Review' FROM Enrol";
    
    $stmt = $conn->prepare($sel_query); 
    
	$Accepted="Accepted";
	$Rejected="Rejected";
	$Under_Review="Under Review";

	
	$stmt->bind_param("sss",$Accepted, $Rejected, $Under_Review);
	$stmt->execute();
	$result = $stmt->get_result(); // get the mysqli result
	  
	if($result->num_rows === 0) exit('No records found!');
	while($row = $result->fetch_assoc()) {  ?>
  
   
<tr>
        
        <td><?php echo $row["Accepted"]; ?></td>
        <td><?php echo $row["Rejected"]; ?></td>
        <td><?php echo $row["Under_Review"]; ?></td>
</tr>




</table>

<?php
class Database {
 
    private $host;
    private $user;
    private $pass;
    private $name;
    private $link;
    private $error;
    private $errno;
    private $query;
 
    function __construct($host, $user, $pass, $name = "", $conn = 1) {
        $this -> host = $host;
        $this -> user = $user;
        $this -> pass = $pass;
        if (!empty($name)) $this -> name = $name;      
        if ($conn == 1) $this -> connect();
    }
 
    function __destruct() {
        @mysql_close($this->link);
    }
 
    public function connect() {
        if ($this -> link = mysql_connect($this -> host, $this -> user, $this -> pass, TRUE)) {
            if (!empty($this -> name)) {
                if (!mysql_select_db($this -> name, $this->link)) $this -> exception("Could not connect to the database!");
            }
        } else {
            $this -> exception("Could not create database connection!");
        }
    }
 
    public function close() {
        @mysql_close($this->link);
    }
 
    public function query($sql) {
        if ($this->query = @mysql_query($sql, $this->link)) {
            return $this->query;
        } else {
            $this->exception("Could not query database!");
            return false;
        }
    }
 
    public function num_rows($qid) {
        if (empty($qid)) {         
            $this->exception("Could not get number of rows because no query id was supplied!");
            return false;
        } else {
            return mysql_num_rows($qid);
        }
    }
 
    public function fetch_array($qid) {
        if (empty($qid)) {
            $this->exception("Could not fetch array because no query id was supplied!");
            return false;
        } else {
            $data = mysql_fetch_array($qid);
        }
        return $data;
    }
 
    public function fetch_array_assoc($qid) {
        if (empty($qid)) {
            $this->exception("Could not fetch array assoc because no query id was supplied!");
            return false;
        } else {
            $data = mysql_fetch_array($qid, MYSQL_ASSOC);
        }
        return $data;
    }
 
public function fetch_object($qid) {
        if (empty($qid)) {
            $this->exception("Could not fetch object assoc because no query id was supplied!");
            return false;
        } else {
            $data = mysql_fetch_object($qid);
        }
        return $data;
    }
 
    public function fetch_all_array($sql, $assoc = true) {
        $data = array();
        if ($qid = $this->query($sql)) {
            if ($assoc) {
                while ($row = $this->fetch_array_assoc($qid)) {
                    $data[] = $row;
                }
            } else {
                while ($row = $this->fetch_array($qid)) {
                    $data[] = $row;
                }
            }
        } else {
            return false;
        }
        return $data;
    }
 
    public function last_id() {
        if ($id = mysql_insert_id()) {
            return $id;
        } else {
            return false;
        }
    }
 
    private function exception($message) {
        if ($this->link) {
            $this->error = mysql_error($this->link);
            $this->errno = mysql_errno($this->link);
        } else {
            $this->error = mysql_error();
            $this->errno = mysql_errno();
        }
        if (PHP_SAPI !== 'cli') {
        ?>
 
            <div class="alert-bad">
                <div>
                    Database Error
                </div>
                <div>
                    Message: <?php echo $message; ?>
                </div>
                <?php if (strlen($this->error) > 0): ?>
                    <div>
                        <?php echo $this->error; ?>
                    </div>
                <?php endif; ?>
                <div>
                    Script: <?php echo @$_SERVER['REQUEST_URI']; ?>
                </div>
                <?php if (strlen(@$_SERVER['HTTP_REFERER']) > 0): ?>
                    <div>
                        <?php echo @$_SERVER['HTTP_REFERER']; ?>
                    </div>
                <?php endif; ?>
            </div>
        <?php
        } else {
                    echo "MYSQL ERROR: " . ((isset($this->error) && !empty($this->error)) ? $this->error:'') . "\n";
        };
    }
 
}
?>