Battle Compressor for 0?

[Simwar]

Can you get 0 cards with Battle Compressor?
I was under the impression that you had to pick at least 1 card. Otherwise you would be playing a card for no effect.

Also is there no way to look through older questions on PokeGym? I feel like this question has been asked before, but I couldn't find an answer anywhere.

 

[PokePop]

You have to get at least one.
There is a search function in the yellow bar that runs across the top of the forum.