Thanks for answer my question.
if i create new forum in new course it work well.
But I want to do move form with posts. And I don't want to create a new form in my course. Becouse there are a lot of forum. I can move forum name in a new course but discussions can't move when change mdl_forum_discussions forum and course no. i can't find why it doesn't work?
i change
mdl_forum_discussions table forum and course no
mdl_forum table course numbers.
thanks