Corn sugar is just D-glucose, or dextrose. Table sugar is sucrose, which is 50%/50% levulose/D-glucose. Glucose is the right-hand molecule, and levulose is the left-hand molecule. Beet sugar is also just sucrose.
During sugar refining, the manufacturer removes sugar from the plant material (sugar cane, beets, dates, etc.), and then removes the remaining plant material from the sugar. Plain white sugar is basically only sucrose. Sucrose is sucrose, no matter where it came from. Chemically, white sugar from beets is identical to white sugar from canes.
Yeast have enzymes that break sucrose into dextrose/levulose, so they have no problem eating sucrose, levulose, or dextrose. How they metabolize each sugar is pretty much the same. I've read that some breweries that make weizens will add dextrose to their wort because it encourages yeast to make either 4VG or isoamyl acetate, I can't remember which one.
Candi syrup is made from sucrose that has been cooked into a dark syrup by a bit of caramelization, and a lot of Maillard reactions.