php - 无法运行查询 : SQLSTATE[HY093]: Invalid parameter number: number of bound variables does not match number of tokens

Question

我这里有个问题。我不断收到此错误，即绑定(bind)变量的数量与 token 的数量不匹配。我仔细检查了我的代码，似乎没有错误。不管怎样，我对这些 PDO 还很陌生。

这是我如何调用数据库中的数据以在表单中回显的代码

if(isset($_GET['idstudent'], $_GET['idbook'])){
$_SESSION['link']=$_GET['idstudent'];
$_SESSION['link2']=$_GET['idbook'];
$sessionidstudent = $_SESSION['link'];
$sessionidbook = $_SESSION['link2']; }  


$query = " 
    SELECT 
        * 
    FROM viewlibrary
    WHERE 
        id = :sessionidstudent AND
        serialno = :sessionidbook

"; 

$query_params = array( 
    ':sessionidstudent' => $_SESSION['link'],
    ':sessionidbook' => $_SESSION['link2'] 
); 

try 
{ 
    $stmt = $db->prepare($query); 
    $result = $stmt->execute($query_params); 
}
catch(PDOException $ex) 
{ 
    die("Failed to run query: " . $ex->getMessage()); 
}
$r=$stmt->fetch(PDO::FETCH_ASSOC);    ?>

这是我的 HTML 代码

<form action="editpage.php" method="post" class="login, reminder">
<p>Student Matric Number:
    <input type="text" class="login-input" name="addmatricno" id="addmatricno" value="<?php echo $r['matricno'] ?>" placeholder="Enter student matric number">
    Student Name:
    <input type="text" class="login-input" name="addname" id="addname" value="<?php echo $r['studentname'] ?>" placeholder="Enter student name">
    Programme:
    <input type="text" class="login-input" name="addprogramme" id="addprogramme" value="<?php echo $r['programme'] ?>" placeholder="Enter student programme">
    Education Level:

    <?php

        if($r['education_level'] == "PHD"){
            echo '<select name="selectedulevel" id="selectedulevel" class="login-input">';
            echo '<option disabled>Please select education level</option>';
            echo '<option value="PHD" selected>PHD</option>';
            echo '<option value="MASTER">MASTER</option>';
            echo '<option value="PHD">DEGREE</option></p></select>';
        }
        else if($r['education_level'] == "MASTER"){
            echo '<select name="selectedulevel" id="selectedulevel" class="login-input">';
            echo '<option disabled>Please select education level</option>';
            echo '<option value="PHD">PHD</option>';
            echo '<option value="MASTER" selected>MASTER</option>';
            echo '<option value="PHD">DEGREE</option></p></select>';
        }
        else{
            echo '<select name="selectedulevel" id="selectedulevel" class="login-input">';
            echo '<option disabled>Please select education level</option>';
            echo '<option value="PHD">PHD</option>';
            echo '<option value="MASTER">MASTER</option>';
            echo '<option value="PHD" selected>DEGREE</option></p></select>';
        }

    ?>
    <input type="submit" name="updatestudent" id="updatestudent" value="Update Student" class="login-submit" style = "width: 20%; text-align: center">

最后但并非最不重要的一点是我的查询代码。

$query = " 
        UPDATE student
            SET
                matricno = :addmatricno,
                studentname = :addname,
                programme = :addprogramme,
                education_level = :selectedulevel
            WHERE
                id = :sessionidstudent
    "; 

    $query_params = array( 
        ':addmatricno' => $_POST['addmatricno'], 
        ':addname' => $_POST['addname'], 
        ':addprogramme' => $_POST['addprogramme'], 
        ':selectedulevel' => $_POST['selectedulevel']
    ); 

    try 
    { 
        // Execute the query to create the user 
        $stmt = $db->prepare($query); 
        //$stmt->bindValue(':sessionidstudent',$sessionidstudent);
        $result = $stmt->execute($query_params); 
    } 
    catch(PDOException $ex) 
    { 
        // Note: On a production website, you should not output $ex->getMessage(). 
        // It may provide an attacker with helpful information about your code.  
        die("Failed to run query: " . $ex->getMessage()); 
    }


    // This redirects the user back to the login page after they register 
    echo '<script language="javascript">';
    echo 'alert("Info updated successful.")';
    echo '</script>'; 
    header("Refresh: 0; updatebooks.php"); 
    die(); 

注意:$db 引用 $db = new PDO("mysql:host={$host};dbname={$dbname};charset=utf8", $username, $password, $options); 我把其他文件放在其中，我可以确定我与数据库的连接完全没有问题。我已经多次检查我的代码，但仍然遇到相同的错误。

Answer 1

在查询参数变量中，您忘记在更新查询中添加 :sessionidstudent，添加该变量，错误就会消失