题目内容

下面有关HAVING子句,说法不正确的是_________。

A. 使用HAVING子句的作用是过滤掉不满足条件的分组
B. 使用HAVING子句的同时不能使用WHERE子句
C. 使用HAVING子句的同时可以使用WHERE子句
D. HAVING子句必须与GROUP BY 子句同时使用,不能单独使用

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在SQL中,与"NOT IN"等价的操作符是_________。

A. <> ALL
B. = any
C. <> any
D. = ALL

以下定义的4个视图中,能够进行更新操作的是_________。

A. CREATE VIEW S_G(学号,姓名,课程名,分数) AS SELECT S.学号,姓名,课程名,分数 FROM student S,score SC,course C WHERE S.学号=S学号AND S课程号 = 课程号;
B. CREATE VIEW S_AVG(学号,平均分) AS SELECT 学号,AVG(分数) FROM scoreWHERE 分数IS NOT NULL GROUP BY 学号;
CREATE VIEW S_MALE(学号,姓名) AS SELECT 学号,姓名 FROM student WHERE 班号='09031';
D. CREATE VIEW S_FEMALE(姓名,出生日期) AS SELECT 姓名,出生日期 FROM student WHERE 性别='女';

已知选课关系SC(Sno char(8), Cno char(8), GRADE integer),Sno学号,Cno课程号,GRADE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 Sno,SUM(GRADE) as Sgrade FROM SC WHERE GRADE>=60 and COUNT(*)>=4 GROUP BY Sno ORDER BY Sgrade DESC;
B. SELECT Sno,SUM(GRADE) as Sgrade FROM SC WHERE GRADE>=60 GROUP BY Sno HAVING COUNT(*)>=4 ORDER BY Sgrade;
C. SELECT Sno,SUM(GRADE) as Sgrade FROM SC WHERE GRADE>=60 HAVING COUNT(*)>=4 GROUP BY Sno ORDER BY Sgrade DESC;
D. SELECT Sno,SUM(GRADE) as Sgrade FROM SC WHERE GRADE>=60 GROUP BY SnoHAVING COUNT(*)>=4 ORDER BY Sgrade DESC;

已知选课关系SC(Sno char(8), Cno char(8), GRADE integer),Sno学号,Cno课程号,GRADE成绩。检索选修课程'C2'的学生中成绩最高的学生的学号。正确的SELECT语句是_________。

A. SELECT Sno FROM SC WHERE Cno='C2' AND GRADE >= ALL(SELECT GRADE FROM SC WHERE Cno='C2');
B. SELECT Sno FROM SC WHERE Cno='C2' AND GRADE IN (SELECT GRADE FROM SCWHERE Cno='C2');
C. SELECT Sno FROM SC WHERE Cno='C2' AND GRADE >=(SELECT GRADE FROM SCWHERE Cno='C2');
D. SELECT Sno FROM SC WHERE Cno='C2' AND GRADE NOT IN(SELECT GRADE FROM SC WHERE Cno='C2');

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