使用PHP向MySQL数据库中的收件人发送电子邮件

我正在开发一个网站，当一个人在邮箱中输入电子邮件时，它会将其保存到MySQL数据库中

我想做一个网页，一旦访问，将发送电子邮件给数据库中的收件人。我的脚本如下：

$servername = "localhost";
$username = "username";
$password = "password";
$dbname = "dbname";

// Create connection
$conn = new mysqli($servername, $username, $password, $dbname);
// Check connection
if ($conn->connect_error) {
    die("Connection failed: " . $conn->connect_error);
} 

$sql = "SELECT email FROM subscribers";
$result = $conn->query($sql);

if (mysqli_num_rows($result) > 0) {
    // output data of each row
    while($row = mysqli_fetch_assoc($result)) {
       echo $row["email"]. "&nbsp";
    }
} else {
    echo "0 results";
}

$to = "";
$subject = "PrakashSoft Website has been Lauched!";
$txt = "Respected Mam/Sir,

    PrakashSoft Website has been lauched from 3rd May 2015! To visit the website use the following link:

    http://www.prakashsoft.esy.es/home.php";
$headers = "From: noreply@prakashsoft.esy.es";

mail($to, $subject, $txt, $headers);
$conn->close();

因此，我正在尝试从DB获取多封电子邮件，然后向他们发送我键入的电子邮件。我该怎么做呢？我知道我把

$to=“”空白。
试试这个

  $sql = "SELECT GROUP_CONCAT(DISTINCT email)
    FROM subscribers";
if (mysqli_num_rows($result) > 0) {
    while($row = mysqli_fetch_assoc($result)) {
      $to = $row["email"];
} else {
    echo "0 results";
}

这将起作用
$to='mail1，mail2，mail3'警告：mysql_query（）[function.mysql query]：第14行/home/u808741660/public_html/working/email.php中用户'localhost'@'10.2.1.20'（使用密码：NO）的访问被拒绝
警告：mysql_query（）[function.mysql query]：无法在第14行的/home/u808741660/public_html/working/email.php中建立到服务器的链接。警告：mysql_fetch_array（）希望参数1是资源，布尔值在第16行的/home/u808741660/public_html/working/email.php中给出
$servername = "localhost";
$username = "username";
$password = "password";
$dbname = "dbname";

// Create connection
$conn = new mysqli($servername, $username, $password, $dbname);
// Check connection
if ($conn->connect_error) {
    die("Connection failed: " . $conn->connect_error);
}    

$sql = mysql_query("select email from subscribers");
    $recipients = array();
    while($row = mysql_fetch_array($sql)) {
        $recipients[] = $row['email'];
    }

    $to = implode(",", $recipients);
    $subject = "E-mail subject";
    $body = "E-mail body";
    $headers = "From: noreply@prakashsoft.esy.es" ;

    mail($to, $subject, $body, $headers);