关系代数练习-学生选课（题干）.docx根据附件内容，查询学生所有可能的选课情况，正确的SQL语句是（）。
选项：
select sname,cname from student  cross join course;#select sname,cname from student join course on student.sno=course.cno;#select sname,cname from student  join course join sc on student.sno=sc.sno and sc.cno=course.cno;#select sname,cname from student outer join course;