问题详情

检索选修四门以上课程的学生总成绩，并要求按总成绩的降序排列出来。正确的SELECT语句是()。

A.SELECT SNO, SUM (GRADE) FROM SC GROUP BY SNO ORDER BY 2 DESC HAVING COUNT(*) >= 4;

B.SELECT SNO, SUM (GRADE) FROM SC GROUP BY SNO HAVING COUNT(*)>=4 ORDER BY 2 DESC;

C.SELECT SNO, SUM (GRADE) FROM SC HAVING COUNT(*)>=4 GROUP BY SNO ORDER BY 2 DESC;

D.SELECT SNO, SUM (GRADE) FROM SC ORDER BY 2 DESC GROUP BY SNO HAVING COUNT(*)>=4;