I would like to know if the Mijia Bedside Lamp (WIFI + Bluetooth) has gateway and can be used with the Xiaomi Door Sensor?
As far as I know, no. It has BLE (Bluetooth Low Energy) gateway. You need Zigbee (Xiaomi Gateway) in order to use Door sensor.
So, what devices can be used with the lamp?
Well, there are not that much, but it will probably grow over time, i.e.:
Thank you very much