bind_param語句錯誤

Question

我的代碼有什麼問題嗎？我一直在爲bind_param語句發送致命錯誤。它聲明「調用第35行的C：\ xampp \ htdocs \ 1102824H \ Assignment2 \ copyspeech.php中的非對象的成員函數bind_param（）」。請幫忙。謝謝。

<?php 

    session_start(); 

    // default user's name 
    $user = ''; 

    // if visitor is logged in 
    $loggedIn = (!empty($_SESSION['user'])); 

    // since user is logged in, let us retrieve user's name from $_SESSION 
    if ($loggedIn) { 
     $user = $_SESSION['user']; 
    } else { 
     // we only allow logged in user to see this page 
     // if visitor not logged in, redirect visitor to login page 
     header('Location: index.php'); 
     exit; 
    } 

    $speechID = $_GET['id']; 

    // the file that contains your database credentials like username and password 
    require_once('config/database.php'); 

    // see Lecture Webp_Week13_14_Using_PHPandMySQL(updating).pptx Slide 4 aka Step 1 
    $mysqli = new mysqli($database_hostname, $database_username, $database_password, $database_name) or exit("Error connecting to database"); 

    // Slide 5 aka Step 2 
    $stmt = $mysqli->prepare("INSERT INTO assignment_speeches (id, subject, body, tags, image) 
           SELECT id, subject, body, tags, image 
           FROM assignment_speeches 
           WHERE id = ?"); 

    // Slide 6 aka Step 3 the bind params must correspond to the ? 
    $stmt->bind_param("i", $speechID); // 1 ? so we use i. we use i because id is INT 

    // Slide 7 aka Step 4 
    $successfullyCopied = $stmt->execute(); 

    // Slide 8 aka Step 5 
    // we won't check the delete result here. 

    // Slide 9 aka Step 6 and 7 
    $stmt->close(); 

    $mysqli->close(); 

    // if we successfully delete this, we 
    if ($successfullyCopied) { 
     $_SESSION['message'] = 'Successfully copied'; 
    } else { 
     $_SESSION['message'] = 'Unable to copy'; 
    } 

    header('Location: homepage.php'); 

？>

Answer 1

查詢的語法不正確。這就是爲什麼prepare()和隨後致電bind_param()失敗。在查詢

變化

SELECT (id, subject, body, tags, image) 

到

SELECT id, subject, body, tags, image 

UPDATE的SELECT條款刪除括號由於id是auto_increment列，您還需要從列排除列表，讓MySQL的產生被複制行的新ID

INSERT INTO assignment_speeches (subject, body, tags, image) 
SELECT subject, body, tags, image 
    FROM assignment_speeches 
WHERE id = ?