在PHP中选择多个数据库，但分别打印ID

<?php
// 连接第一个数据库
$host1 = "数据库1的主机名";
$username1 = "数据库1的用户名";
$password1 = "数据库1的密码";
$dbname1 = "数据库1的名称";

$conn1 = mysqli_connect($host1, $username1, $password1, $dbname1);
if (!$conn1) {
    die("连接数据库1失败: " . mysqli_connect_error());
}

// 连接第二个数据库
$host2 = "数据库2的主机名";
$username2 = "数据库2的用户名";
$password2 = "数据库2的密码";
$dbname2 = "数据库2的名称";

$conn2 = mysqli_connect($host2, $username2, $password2, $dbname2);
if (!$conn2) {
    die("连接数据库2失败: " . mysqli_connect_error());
}

// 查询并打印第一个数据库的ID
$sql1 = "SELECT id FROM table1";
$result1 = mysqli_query($conn1, $sql1);
if (mysqli_num_rows($result1) > 0) {
    while ($row = mysqli_fetch_assoc($result1)) {
        echo "数据库1的ID: " . $row["id"] . "<br>";
    }
} else {
    echo "数据库1中没有数据";
}

// 查询并打印第二个数据库的ID
$sql2 = "SELECT id FROM table2";
$result2 = mysqli_query($conn2, $sql2);
if (mysqli_num_rows($result2) > 0) {
    while ($row = mysqli_fetch_assoc($result2)) {
        echo "数据库2的ID: " . $row["id"] . "<br>";
    }
} else {
    echo "数据库2中没有数据";
}

// 关闭数据库连接
mysqli_close($conn1);
mysqli_close($conn2);
?>