我想了解为什么下面的脚本不起作用。不断获取错误：致命错误：函数wpdb：：prepare（）的参数太少，传递了1个。。。应为2。。。不知道我需要从哪里得到第二个论点。

<?php

$zoekvn = $_POST[\'zoekvn\']

if(isset($_POST[\'submit\'])):


    try{
        $result = $wpdb->get_results($wpdb->prepare("SELECT id, geslacht, voornaam, familienaam, email, tel, afile, app_datum FROM sollicitatie_form WHERE voornaam = $zoekvn"));

        foreach ($result as $row){?>


        <form>

            <tr>
            <td><?php echo "{$row -> id}"; ?></td>
            <td><?php echo "{$row -> geslacht}"; ?></td>
            <td><?php echo "{$row -> voornaam}"; ?></td>
            <td><?php echo "{$row -> familienaam}"; ?></td>
            <td><?php echo "{$row -> email}"; ?></td>
            <td><?php echo "{$row -> tel }"; ?></td>
            <td><a href="sollicitatie/uploads/<?php echo "{$row -> afile}" ?>" target="_blank">view file</a></td>
            <td><?php echo "{$row -> app_datum}"; ?></td>


        </tr>

        </form>


        <?php
        }
    }

        // use exec() because no results are returned
        catch(PDOException $e)
        {
        echo $sql . "<br>" . $e->getMessage();
        }

$conn = null;
endif;
?>