I play piano at - Tradução em português

Hey!

''I play the piano in a restaurant at night

If you define wich restaurant you can use "at", as in Nate Butler playing the piano at The Daily Planet Restaurant.

If you do it in a regular way (repeated actions) you could use some conjunctions to express that, for example, I play the piano every night in a restaurant, etc.
Many people would be a stickler for grammar , so they would suggest you to say "play the piano".

lol..

In fact both would be understood by me, though there is an old rule that says with instruments (mainly piano) it would go with the article "the". In an academical work one should use the rule of using "the" in the sentence.

http://www.english-test.net/forum/ftopic38365.html

Thank you

It´s my pleasure to help out another learner, you´re welcome.