I live in Slovakia and in certain parts this is a very common thing - if you’re about to have a birthday/wedding/any other gathering, you book a restaurant or some bigger place, you agree on what meal they should prepare for you and they prepare tables. The waitresses are there for you as usual.
But when it comes to alcohol and drinks in general, the restaurant doesn’t serve it, you bring your own and also serve it.
I always found it weird that we bring our own alcohol to a restaurant even though the restaurant offers alcohol aswell.
Is this common in your country also? Do you bring other things for a party/gathering in a restaurant?
No, you just get the alcohol from the restaurant in Spain - I’d think they would get quite mad at you if you were to bring up a wine bottle to the table.