Sql查询多个表yii2

// 定义模型类
class User extends \yii\db\ActiveRecord
{
    public static function tableName()
    {
        return 'user';
    }

    public function getOrders()
    {
        return $this->hasMany(Order::className(), ['user_id' => 'id']);
    }
}

class Order extends \yii\db\ActiveRecord
{
    public static function tableName()
    {
        return 'order';
    }

    public function getUser()
    {
        return $this->hasOne(User::className(), ['id' => 'user_id']);
    }
}

// 编写查询代码
$users = User::find()
    ->joinWith('orders')
    ->where(['status' => 'active'])
    ->orderBy('username')
    ->all();

foreach ($users as $user) {
    echo $user->username;
    foreach ($user->orders as $order) {
        echo $order->order_number;
    }
}