select stu.name,course.*from stu,course,chice where stu.sid=chice.sid and course.c_id=choice.c_idand stu.name='张三' --这个地方输入你想查的人名,如果这句不写则查询全部
select a.sid from stu a join choice b on a.sid=b.s_id join course c on c.c_id=b.c_id