While we generally focus on glucose, sucrose, and fructose for brewing, there are a lot of sugars out there. Can all of these be used in the brewing process, particularly for beer? What are the effects of using more esoteric sugars such as dextrose, xylose, mycose, or mannose alongside normal brewing grains? What about amino sugars such as glucosamine?
Some sugars won't start a fermentation with brewer's yeast at all, such a lactose. In such case, sooner or later other organisms would take over (e.g. lactobacteria).
Any sugars that can be fermented, would ferment at different speeds. As there is usually more than one kind of sugar present, the easy ones ferment first until the alcohol kills off the yeast, leaving the more difficult ones behind. Fermentation usually continues at that point, just a lot more slowly.
The difference in the effect is minor as long as everything is fully fermented. An example of such a difference is fruit wines and beer. Fruit wines contain minor amounts of methanol while beer usually does not. Differences in flavour are more about what is not fermented.
Mannose can definitely be fermented by brewer's yeast. Dextrose is just another name for glucose.