Diff between ( rake db:migrate VERSION0 ) and (rake db:rollback)

what is the difference between
rake db:migrate VERSION=0
and
rake db:rollback

the only one i have seen is first one always works and second one
gives error sometimes. …but i guess both try to do the same
thing.
??

vipin

rollback goes back to the previous version. VERSION= enables you to jump
at any spot in time. But if I recall correctly you can also pass an
option to rollback so that it rolls back more than 1 step, but I have
never used it.