There are no friendly gyms within comfortable walking distance of my home. I'm starting to think the only way to train my Pokémon might be to battle with the gyms that are available (and I would lose miserablely, often).
Do battles train (benefit) my Pokémon in a way that is comparable to training? (Because from what I see there is no other way to train my Pokémon.) Is there a difference in the amount of XP earned (of you win)?
Your train at gyms owned by your team. You get one Pokemon to battle with and each opponent you defeat increases the XP earned. This is how you level up a gym. If your Pokemon loses, it is at 1 HP.
You battle a gym owned by an opposing team. You get 6 Pokemon to use and each Pokemon you defeat decreases the XP of the gym. Any Pokemon that lose during your battle are at 0 HP and require a revive. When the gym his level 0, no team controls it until a Pokemon is put in (usually the person that defeated the gym will take it but it's possible for another player to get there first).
Neither of these actions level up your Pokemon or the Pokemon in the gym.
Training gyms makes it a higher level the gym. With a higher level more people can defend the gym.
Battling a gym lets you take it over for your chosen team.
