(单选题)17: ? ?检索选修四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 SCWHERE GRADE>=60GROUP BY S#ORDER BY 2 DESCHAVING COUNT（*）>=4

B: SELECT S#，SUM（GRADE）FROM SCWHERE GRADE>=60GROUP BY S#HAVING COUNT（*）>=4ORDER BY ?2 ?DESC

C: SELECT S#，SUM（GRADE）FROM SCWHERE GRADE>=60HAVING COUNT（*）>=4GROUP BY S#ORDER BY ?2 ?DESC

D: DELECT S#，SUM（GRADE）FROM SCWHERE GRADE>=60ORDER BY ?2 ?DESC?GROUP BY S#HAVING COUNT（*）>=4

正确答案:♦B♦