I feel a bit of a numpty for having to ask. I've always been a beer or wine drinker which is nice and simple when ordering at a bar.
But recently I've been introduced to gin and now I'm given loads of choices with what to have with it. 
I always thought it was just a G&T but some places offer soda as an alternative. Is that just fizzy water? Should know this at my age!
Also, do the more seasoned spirit drinkers have any recommendations? Rhubarb gin and elderflower tonic seems to be the winning combo so far.