The term "bartending" has also been termed "beverage management" and "mixology" so you may term a bartender as a mixologist or a beverage manager. However, I haven't seen any iron-clad evidence that there is an official technical term for bartender.
The bartender is the primary sales vehicle for a bar establishment. He or she interacts with the clientele and puts a human face to the fantasy that the bar is trying to 'sell' (a theme, etc.). The actual making of drinks comes second to this. To be really effective at bartending is to thoroughly understand a bar's fantasy and serve drinks in accordance with it. That being said, what is tangible about bartending is the serving process, which is what makes the bartender (and the establishment) money.
Another name for a roof worker is roofer.
HAT IS ANOTHER NAME FOR NATIONAL SOCIALIST GERMAN WORKER and PARTY?
They are sometimes referred to as a social welfare worker.
employee, hireling, jobholder
a hard worker