设有关系模式:student(sno,sname,age,dept),现利用命令: CREATE VIEW stu AS SELECT * FROM student WHERE dept="cs"WITH CHECK OPTION创建了一个视图。则以下SQL命令中能正确执行的是( )。
A.UPDATE stu SET dept="maths"
B.UPDATE stu SET dept="maths"WHERE age>=20
C.INSERT INTO stu VALUES("2004001","John",30,"CS")
D.INSERT INTO stu VALUES("200400l","John",50,"maths")
第1题:
设有关系模式:student(sno, sname, age, dept),现利用命令: CREATE VIEW stu AS SELECT *FROM student WHERE dept="cs"WITH CHECK OPTION 创建了一个视图。则以下SQl命令中能正确执行的是
A.UPDATE stu SET dept="maths"
B.UPDATE stu SET dept="maths"WHERE age>=20
C.INSERT INTO stu VALUES ("2004001", "John", 30, "cs")
D.INSERT INTO stu VALUES ("2004001", "John", 50, "maths")
第2题:
对于学生信息表S(SNUMBER,SNAME,SEX,AGE,DEPT)(STUDENT由学号SN0,姓名SNAME,性别SEX,年龄AGE,所在系DEPT5个属性组成,其中SNUMBER为主码),求年龄20~23岁之间的学生姓名和年龄,正确的语句是( )。
A) SELECT SNAME, AGE FROM S WHERE AGE>20 OR AGE<23
B) SELECT SNAME, AGE FROM S WHERE AGE BETWEEN 20 AND 23
C) SELECT * FROM S WHERE AGE BETWEEN 20 AND 23
D) 以上均不正确
第3题:
(40)查找学生姓名及其所选修课程号和成绩,正确的 SQL 语句是
A)SELECT sname FROM student, SELECT cno,grade FROM sc WHERE student.sno =sc.sno
B) FROM sname,cno,grade FROM student,course WHERE student.sno =course.cno
C) SELECT sname ,canme,grade FROM student,course,sc WHERE student.sno =sc.sno and sc.c
no=course.cno
D) SELECT sname ,cno,grade FROM student,sc WHERE student.sno =sc.sno
第4题:
根据SQL标准,创建一个视图abc,通过该视图只能对表student中系dept为‘IS’的记录进行更新操作。下面哪条语句适用?()
A create view abc as select * from student where dept=’IS’
B create view abc as select * from student where dept=’IS’ with check option
C create view abc as student where dept=’IS’
D create view abc as select dept=’IS’ from student
第5题:
设有学生数据库:student(sno,sname,sex,age,dept)。现要查询所有刘姓学生的信息,可使用如下的 SQL语句:SELECT*FROM student WHERE【 】。
第6题:
对于学生信息表:student(sno,sname,sex,age,dept),能够得到年龄在20岁到22岁之间的学生的姓名和学号的语句是
A.SELECT * FROM student WHERE age BETWEEN 20 AND 22
B.SELECT sname,sno FROM student WHERE age BETWEEN 20 AND 22
C.SELECT sname,sno FROM student WHERE age>=20
D.SELECT sname,sno FROM student WHERE age<=22
第7题:
以下2题基于以下说明。设有三个关系:
学生关系S(SNO,SNAME,AGE,SEX) (分别代表学生的学号、姓名、年龄、性别)
学习关系SC(SNO,CNO,GRADE) (分别代表学生的学号、课程编号、成绩)
若在关系S中查找姓名中第一个字为′王′的学生的学号和姓名。下面列出的SQL语句中,正确的是
A.SELECT SNO,SNAME FROM S WHERE SNAME=′王%′
B.SELECT SNO,SNAME FROM S WHERE SNAME=′王_′
C.SELECT SNO,SNAME FROM S WHERE SNAME LIKE′王%′
D.SELECT SNO,SNAME FROM S WHERE SNAME LIKE′王_′
第8题:
( 32 ) 设有学生信息关系 STUDENT ( sno , sname , sex , age , dept ) 。 “ 查找信息系 ( IS 系 ) 中年龄小 于20 岁的学生的姓名 ” ,该操作正确的关系代数表达式是
Ⅰ . π sname ( σ dept= ’ IS ’ ∧ age<20( STUDENT ))
Ⅱ . σ dept= ’ IS ’ ∧ age<20 ( π sname ( STUDENT ))
Ⅲ . σ sname ( π dept= ’ IS ’ ∧ age<20( STUDENT ))
A )仅 Ⅰ
B )仅 Ⅱ
C ) Ⅰ 和 Ⅱ
D ) Ⅱ 和 Ⅲ
第9题:
根据SQL标准,要查询表student中平均年龄age小于21的所在系dept及其平均年龄值,下面哪条语句适用?()
A select dept,avg(age) from student where avg(age)<21
B select dept,avg(age) from student group by dept having avg(age)<21
C select dept,avg(age) from student having avg(age)<21
D select dept,avg(age) from student group by dept where avg(age)<21
第10题:
根据SQL标准,下面哪句语句能够找出年龄最小的同学?其中age为学生表student中的年龄字段,sno为学生的学号。()
A select max(age) from student
B select sno from student where age = max(age)
C select sno from student having age = max(age)
D select sno from student a where a.age<= (select min(b.age) from student b)