what are the oxygen level in different planets ?

Look it up yourself - we aren't your slaves.

Earth -- about 20% oxygen

all other planets and moons -- oxygen about 0%

It varies a lot. Why can't you google it?

There is hardly any free oxygen anywhere but here.

Oxygen is a very highly reactive gas. It can't stay in an atmosphere long unless something is constantly producing it, like life. So Earth is the only planet or moon or body with any oxygen. 

Near enough to zero, except on Earth.

Other than earth, the planets that have oxygen (Mars, Venus) have it in the form of CO2 and/or water.  Not oxygen you could breathe.  The giant planets' atmospheres are more hydrogen, helium, and hydrocarbons.

There are Various amounts on Various Planets

Mercury has actually a very thin Atmosphere of Oxygen

As has Jupiter's moon Europa

Trace amounts elsewhere, even on Asteroids

there is no free oxygen in any of the planets in our solar system.