题目内容:
在Oracle中,以下是STUDENTS表的结构: SID NUMBER NOT NULL,Primary Key SNAME VARCHAR2(30) COURSE_ID VARCHAR2(10) NOT NULL MARKS NUMBER 你需要查询参加了课程ID为C10的考试,并且分数排在前10名的学生,以下( )语句能够实现此功能。SELECT SID,marks,ROWNUM "Rank" FORM studentsA.WHERE ROWNUM<=10 AND course_id=.C10. ORDER BY marks DESC;SELECT SID,marks,ROWNUM"Rank" FORM students
B.WHERE ROWNUM<=10 AND course_id=.C10. ORDER BY marks;SELECT SID,marks,ROWNUM"Rank" FORM (SELECT SID ,marks FORM students
C.WHERE ROWNUM<=10 AND course_id=.C10.) ORDER BY marks DESC;SELECT SID,marks,ROWNUM"Rank" FORM (SELECT SID ,marks FORM students
D.WHERE course_id=.C10. ORDER BY marks DESC) WHERE ROWNUM<=10;
参考答案: