Due to the diffrences in constituition from place to place, can i study law in a country and work in another?

Yes bt u must be 'called' to that country's bar b4 u can be allow to practice there i.e u can only serve in a country wn u ve bn cald to their bar. U cn also be cald to more dan 1 bar provided u gt trained.

nope...how can you work there if you don't understand the way they operate.
unless you study there for a while

I know if study law in Nigeria you can practice in the UK and other countries that their law have a British semblance. But you can't practice in places like USA or Canada because their law practice Is different from the British system

Yes you can study Law in USA,England,Canada et.c and still be qualify to practise law in Nigeria provided you pass the Bar part1&2 exams.And to those saying their constitution is different,yes you are right but the thing is you are taught "how to practise law" in school and you don't really need to be grounded in the existing laws of that country.