单项选择题若要查询每门课成绩的平均成绩,且要求查询结果按平均成绩升序排列,平均成绩相同时,按课程号降序排列,可用SQL语言写为()
A.SELECT Cno,AVG(Score)FROM SCS <br> GROUP BY Score ORDER BY 2.Cno DESC
B.SELECT Cno,AVG(Score) FROM SCS <br> GROUP BY Cno ORDER BY 2.Cno DESC
C.SELECT Cno,AVG(Score) FROM SCS <br> ORDER BY Cno DESC ORDER BY Score
D.SELECT Cno,AVG(Score) FROM SCS <br> GROUP BY AVG(Score) ORDER BY Cno DESC