WordPress:PHP 删除每个周期中的数据库行

Question

大家好，我对PHP开发很陌生。

我正在编写一个 smiple 脚本来从 url 获取和发送电子邮件，循环浏览数据库表中的某些行，并在找到该行时将其删除。

除了删除该行之外，我得到了所有内容。我真的很感激有人告诉我我的错误，以帮助我理解。我认为错误在于 WHERE 条件。

我收到的错误消息是：错误：无法从 [e-mail]==[e-mail] wp_email_address_db执行删除。

    <?php
$path = $_SERVER['DOCUMENT_ROOT']; 
include_once $path . '/wp-load.php';
global $wpdb;
//sanatise and lowercase email addy from URL
$emailToRemove = filter_var ( strtolower($_GET["usermail"]), FILTER_SANITIZE_EMAIL);
//get DB table
$data = $wpdb->get_results("SELECT * FROM wp_email_address_db`");
    foreach ($data as $d) {
        //sanatise and lowercase email addy from DB
        $email = filter_var ( strtolower($d->email_address), FILTER_SANITIZE_EMAIL);
        //check if the email addy is in this row
        if($email == $emailToRemove){
            //get info
            echo 'true <br/>';
            echo 'id: '.$d->id.'<br/>';
            //I need to delete this row
            $sql = "DELETE FROM wp_email_address_db WHERE $email = $emailToRemove";
            if(mysqli_query($link, $sql)){
                echo "Records were deleted successfully.";
            } else{
                echo "ERROR: Could not able to execute $sql. " . mysqli_error($link);
            }
        } 
}

// $columnTitles = ['id','email_address','imported_via'];
?>

Answer 1

您在email中有一个拼写错误，并且 where 子句中的值应该在单引号内：

将其更改为：

        $sql = "DELETE FROM wp_email_address_db WHERE email = '$emailToRemove'";

Answer 2

您的查询应该是这样的：

$sql ="从电子邮件='$emailToRemove'wp_email_address_db中删除";

Answer 3

最好

使用引号(单引号'，双引号"(也用反引号定义列。

查询：

$sql = "DELETE FROM wp_email_address_db WHERE `email` = '".$emailToRemove."'";

您的主要错误是$email哪个应该是此处带有反引号的列名WHERE $email = $emailToRemove

Answer 4

不应该是这样的查询

DELETE FROM wp_email_address_db WHERE email_field_name = '$emailToRemove'

而不是

DELETE FROM wp_email_address_db WHERE $email = $emailToRemove

在您的查询中，您将$email的值作为字段名称传递，我假设字段[e-mail]不存在

Answer 5

尝试替换

$sql = "DELETE FROM wp_email_address_db WHERE $email = $emailToRemove";

跟

$sql = "DELETE FROM wp_email_address_db WHERE '$email' = '$emailToRemove'";

<</div> div class="one_answers">

我删除了foreach，您不需要从数据库中检索所有邮件。此外，我使用准备好的语句来避免SQL注入

这种对数据库执行删除查询的脚本必须受到所有用户的保护。只允许管理员使用此脚本

<?php
$path = $_SERVER['DOCUMENT_ROOT']; 
include_once $path . '/wp-load.php';
// WARNING: You should check the identity of the user performing this action, MySql DELETE action is dangerous 
global $wpdb;
//sanatise and lowercase email addy from URL
$emailToRemove = filter_var ( strtolower($_GET["usermail"]), FILTER_SANITIZE_EMAIL);
$sqlDeleteQuery = '
    DELETE 
    FROM wp_email_address_db 
    WHERE email = ?
';
$statement = mysqli_prepare($link, $sqlDeleteQuery);
// Bind the email to your query (the ? ), this avoid the SQL injection attack
$statement->bind_param('s', $emailToRemove);
if (false !== mysqli_stmt_execute($statement)) {
    die('The MySql query failed ! Error : ' . mysqli_error($link));
}
$emailsDeleted = mysqli_stmt_affected_rows($statement);
echo sprintf('"%d" emails deleted', $emailsDeleted);

我无法尝试上面的代码，所以如果有什么问题，请告诉我:)

Answer 6

通过以下方式解决：

<?php
require_once($_SERVER["DOCUMENT_ROOT"]."/wp-load.php");
if (isset($_GET["usermail"])) {
    global $wpdb;
    $remove = filter_var(strtolower($_GET["usermail"]), FILTER_SANITIZE_EMAIL);
    $wpdb->query("DELETE FROM wp_email_address_db WHERE email_address='$remove'");
    echo "You have successfully been unsubscribed.";
} 
?>