How can I power IP camera from same lan cable as wifi AP over POE?
There are PoE pass through switches.

The issue is that you have multiple devices, IP camera, WAP and the switch is likely to exceed your power budget.

Also the cost of any switches, splitters or injectors that may be able to do this would likely exceed the cost of a short cable run.

Wifi cameras generally suck and your issue is power anyway, IP data is not very power intensive.

If though the cable run for some reason is nigh on impossible, ideally see if there are altenative power sources near your WAP, if so you may be able to install a small PoE switch at that location or possibly a power supply for a camera or the WAP also which removes the need for PoE pass through and a normal switch or small PoE powered switch can be used. Not the finest solution but gives you a bit more options.