如何使用PHP同步两个数据库表？

$db1 = new PDO('mysql:host=host1;dbname=dbname1', 'username1', 'password1');
$db2 = new PDO('mysql:host=host2;dbname=dbname2', 'username2', 'password2');

$stmt = $db1->query('SELECT * FROM table1');
$data1 = $stmt->fetchAll(PDO::FETCH_ASSOC);

$stmt2 = $db2->prepare('INSERT INTO table2 (column1, column2, column3) VALUES (:column1, :column2, :column3)');

foreach ($data1 as $row) {
    $stmt2->bindParam(':column1', $row['column1']);
    $stmt2->bindParam(':column2', $row['column2']);
    $stmt2->bindParam(':column3', $row['column3']);
    $stmt2->execute();
}