Php 警告：mysqli_close（）：无法'；拿不到mysqli

我得到了这个错误：

Warning: mysqli_close(): Couldn't fetch mysqli in sendinvoice.php on line 54

这是我的密码：

    <?php
include 'dbconfig.php';
ob_start();

$taxcb = $_POST['taxcb'];
$taxrate = $_POST['taxrate'];
$bcctocb = $_POST['bcctocb'];
$bcctotxt = $_POST['bcctotxt'];
$duedate = $_POST['duedate'];
$issuedate = $_POST['issuedate'];
$additemscb = $_POST['additemscb'];
$additemname = $_POST['additemname'];
$additemprice = $_POST['additemprice'];
$q = $_POST['rowid'];

$sql="SELECT * FROM clients WHERE id = '".$q."'";

$result = mysqli_query($conn,$sql);

while($row = mysqli_fetch_array($result)) {


$to = $row[email];
$subject = "Invoice Test " . date('m/d/Y h:i:s a', time());
include 'invoice.html';
$message = ob_get_clean();

// Always set content-type when sending HTML email
$headers = "MIME-Version: 1.0" . "\r\n";
$headers .= "Content-type:text/html;charset=UTF-8" . "\r\n";

// More headers
$headers .= 'From: <billing@example.com>' . "\r\n";
if ($bcctocb == "y"){
$headers .= 'BCC: ' . $bcctotxt . "\r\n";
}

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

$sql = "UPDATE clients SET last_billed='" . date("Y-m-d H:i:s") . "' WHERE id=" . $q;

if ($conn->query($sql) === TRUE) {
    echo "New record created successfully";
} else {
    echo "Error: " . $sql . "<br>" . $conn->error;
}

$conn->close();

}

mysqli_close($conn);

?>

---

缩进很难判断，但在某些情况下，您将关闭连接两次

$conn->close();

}

mysqli_close($conn);

这两个都将关闭连接，因此第二个连接将失败。
可能更容易删除
$conn->close（）因为它将始终落在第二个收盘点
 我猜你把面向对象的版本和过程风格的版本搞混了，还是坚持一个吧，我建议你使用OOP

采用OOP风格：

/* do connection */
$mysqli = new mysqli("localhost", "my_user", "my_password", "world");

/* close connection */
$mysqli->close();

/* do connection */
$link = mysqli_connect("localhost", "my_user", "my_password", "world");


/* close connection */
mysqli_close($link);

程序风格：

/* do connection */
$mysqli = new mysqli("localhost", "my_user", "my_password", "world");

/* close connection */
$mysqli->close();

/* do connection */
$link = mysqli_connect("localhost", "my_user", "my_password", "world");


/* close connection */
mysqli_close($link);

参见示例
您可以混合使用这两种方法-不推荐，但它似乎仍然有效-@NigelRen是的，您是ri8:）我同意您的看法，先生，但应该避免。一旦脚本终止，连接将被释放。手动操作没有意义。