教学数据库关系模式为: S(S#,SNAME,AGE,SEX) SC(S#,C#,SCORE) C(C#,CNAME,TEACHER) 统计每个学生选修课程的门数(超过5门的学生才统计)。要求输出学生学号、姓名和选修门数,查询结果按门数降序排列,若门数相同,按学号升序排列。
A、SELECT SC.S#, SNAME,COUNT(C#) FROM SC,S WHREE S.S#=SC.S# GROUP BY SC.S#, SNAME HAVING COUNT(*)>5 ORDER BY 2 DESC, 1;
B、SELECT SC.S#, SNAME,COUNT(C#) FROM SC GROUP BY SC.S#, SNAME HAVING COUNT(*)>5 ORDER BY 2 DESC, 1;
C、SELECT SC.S#, SNAME,COUNT(C#) FROM SC,S WHREE S.S#=SC.S# GROUP BY SC.S# HAVING COUNT(*)>5 ORDER BY 2 DESC, 1;
D、SELECT SC.S#, SNAME,COUNT(C#) FROM SC,S GROUP BY SC.S#, SNAME HAVING COUNT(*)>5 ORDER BY 2 DESC, 1;