基于这样的三个表,即学生表 S、课程表 C 和学生选课表 SC,它们的结构 如下:S(S#,SN,SEX,AGE,DEPT)C(C#,CN)SC(S#,C#,GRADE)其中,S#为,SN 为姓名,SEX 为性别,AGE 为年龄,DEPT 为系别,C#为课程 号,CN 为课程名,GRADE 为成绩。检索选修 4 门以上课程的学生总成绩(不统计不及格的课程),并要求按总成绩的降序排列出来。正确的 SELECT 语句是( )。
A.
SELECT S# , SUM ( GRADE ) FROM SC WHERE GRADE>=60 GROUP BY S# ORDER BY 2 DESC HAVING COUNT ( * ) >=4
B.
SELECT S# , SUM ( GRADE ) FROM SC WHERE GRADE>=60 GROUP BY S# HAVING COUNT ( * ) >=4 ORDER BY 2 DESC
C.
SELECT S# , SUM ( GRADE ) FROM SC WHERE GRADE>=60 HAVING COUNT ( * ) >=4 GROUP BY S# ORDER BY 2 DESC
D.
SELECT S# , SUM ( GRADE ) FROM SC WHERE GRADE>=60 ORDER BY 2 DESC GROUP BY S# HAVING COUNT ( * ) >=4