i add code in wp-config.php
define ('DB_CONFIG_FILE','');
require_once(ABSPATH . 'db-config.php');
/** Sample Configuration 2: Partitioning **/
/**
* This example shows a setup where the multisite blog tables have been
* separated from the global dataset.
*/
$wpdb->add_database(array(
'host' => 'localhost',
'user' => 'root',
'password' => '123456',
'name' => 'test01',
));
$wpdb->add_database(array(
'host' => 'localhost',
'user' => 'root',
'password' => '123456',
'name' => 'test02',
'dataset' => 'blog',
));