I need a wiring diagram for a three terminal lamp socket. It will light a night light in the lamp base or light the main lamp or light both the top and the bottom.

You would not use a 3 terminal lamp socket. What you would use is a 3-way rotary switch.
The basic wiring diagram is usually on the switch. The hot or non-ribbed side of the cord goes to the common side of the switch. Then the two outputs of the switch go to the center of the lamp base and the night light. Finish up he job by connecting the non-ribbed side of the cord to the lamp base and the night light.