It seems that the bigger the city, the more hookups happen at clubs.
I say this because I live in a somewhat small city, have some pretty attractive female friends, a lot of them are single. They go clubbing quite often, but get hit on very rarely (at clubs anyway, day to day they get hit on a lot). When they do, the guys usually just try grinding with them for a while and that's about it These girls are by no means prudes or even close to it, but the most any of them have done with a guy from the club is make out, and even that's pretty rare.
So sure, it's possible, but the basic problem is this: Lots of girls do go clubbing just because they enjoy dancing with their girlfriends. I don't know of a single guy that goes to a club just because they like dancing. Therefore, even leaving the total guy/girl ratio aside, among the girls that are there quite a few are simply not looking to meet anyone, while the vast majority of guys are.
It can be done, but really, there are much better places to meet women.