用SQL语句检索选修课程在5门以上(含5门)的学生的、姓名和平均成绩,并按平均成绩降序排序,正确的命令是( )。
A.
SELECT S.,姓名,平均成绩 FROM S,SC; WHERE S.=SC.; GROUP BY S. HAVING COUNT(*)>=5 ORDER BY 平均成绩 DESC
C.
SELECT ,姓名,AVG(成绩)FROM S,SC; WHERE S.=SC. AND COUNT(*)>=5; GROUP BY ORDER BY 3 DESC C.SELECT S.,姓名,AVG(成绩) 平均成绩 FROM S,SC; WHERE S.=SC. AND COUNT(*)>=5; GROUP BY S. ORDER BY 平均成绩 DESC
D.
SELECT S.,姓名,AVG(成绩) 平均成绩 FROM S,SC; WHERE S.=SC.; GROUP BY S. HAVING COUNT(*)>=5 ORDER BY 3 DESC