设关系模式SCG (S#, C#, grade)中S#为学生学号,C#为课程号,grade为某学号学生学某号课程的考试成绩。今要查询每门课程的平均成绩,且要求查询的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,则用SQL查询语言应为(1)。若查询的结果仅限于平均分数超过80分的,则应(2)。A.Select C#,AVG(grade) From SCG Group by grade Order by 2,C# DescB.Select C#,AVG(grade) From SCG Group by C# Order by 2,C# DescC.Select C#,AVG(grade) From SCG Where C#,AVG Desc Group by gradeD.Select C#,AVG(grade) From SCG Group by AVG(grade) Order by 2,C# Desc

设关系模式SCG (S#, C#, grade)中S#为学生学号,C#为课程号,grade为某学号学生学某号课程的考试成绩。今要查询每门课程的平均成绩,且要求查询的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,则用SQL查询语言应为(1)。

若查询的结果仅限于平均分数超过80分的,则应(2)。

A.Select C#,AVG(grade) From SCG Group by grade Order by 2,C# Desc

B.Select C#,AVG(grade) From SCG Group by C# Order by 2,C# Desc

C.Select C#,AVG(grade) From SCG Where C#,AVG Desc Group by grade

D.Select C#,AVG(grade) From SCG Group by AVG(grade) Order by 2,C# Desc


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