How do you approach a group of girls drinking at a table?

There’s a popular bar in my city that’s halfway between a bar and a club with loud music. Everyone gets a table like at a restaurant, but typically everyone is just drinking. I have not figured out a good way to approach a table of girls yet. I’m usually out with a few of my guy friends at our own table. Do I just walk up to the table of girls and invite them to have a drink with us at our table? Should there be anything that comes before the invite?