In my home language in a very informal situation the English term TABLE MATE is used for a group of people who get together usually to consume alcohol. Is this expression in use in English? Or else is there any other expression used to describe the people who usually meet to have drinks?
I don't know "table mate" to have that meaning. According to Merriam-Webster, a tablemate is a "dining companion". I would say, more broadly, a tablemate is person with whom you share a table, not necessarily for dining.
The closest term I know is "drinking buddies." In essence, drinking buddies are people with whom you hang out and drink. They may or may not be the usual friends you hang out with. They might just be a group you hang out with specifically for drinking. That's how I understand it.
The present study sought to further examine the role of peers on alcohol use and problems among young adults. In particular, we focused on a specific subset of peers in one’s social network mostly for activities related to alcohol use called “drinking buddies.”
convives was originally a French word, but in 2015 it became even the Word of the Day at dictionary.com, so you can use it with confidence.
drinking companions and drinking buddies are longer, but more traditional collocations.