card/make/controller/deletelist.php

<?php

header("Content-type:text/html;charset=UTF-8");
include_once("../../untils/conn.php");

$channel_id = $_GET['channel_id'];

$sql = "UPDATE list SET channel = NULL WHERE channel = :channel_id;
        UPDATE list SET channel_one = NULL WHERE channel_one = :channel_id;
        UPDATE list SET channel_two = NULL WHERE channel_two = :channel_id;";

$stmt = $dbh->prepare($sql);
$stmt->bindParam(':channel_id', $channel_id);
$result = $stmt->execute();

if ($result) {
    echo "更新成功！";
} else {
    echo "更新失败！";
}

?>