关系模式SCS(Sno,Cno,Score)中,Sno是学生,Cno是课程号,Score是成绩。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(33)。若查询结果仅限于平均分数超过85分的,则应(34)。 (51)
A.
SELECT Cno,AVG(Score)FROM SCS GROUP BY Score ORDER BY 2.Cno DESC
B.
SELECT Cno,AVG(Score) FROM SCS GROUP BY Cno ORDER BY 2.Cno DESC
C.
SELECT Cno,AVG(Score) FROM SCS ORDER BY Cno DESC ORDER BY Score
D.
SELECT Cno,AVG(Score) FROM SCS GROUP BY AVG(Score)ORDER BY Cno DESC