用SQL语言检索选修课程在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.
SELECTS.,姓名,平均成绩FROMS,SC; WHERES.=SC.; GROUP BY S.HAVING GOUNT(*)>=5 ORDER BY 平均成绩 DESC
B.
SELECT ,姓名,AVG(成绩)FROMS,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 0RDER BY 3 DESC