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根据SQL标准，要查询表student中所有年龄age小于所有学生的平均年龄的记录，下面哪条语句适用?()A select * from student where ageB select * from student having ageC select * from student a where a.ageD select * from student a where (select avg(b.age) from student b ) >= a.age

题目

根据SQL标准，要查询表student中所有年龄age小于所有学生的平均年龄的记录，下面哪条语句适用?()

A select * from student where age< avg(age)

B select * from student having age< avg(age)

C select * from student a where a.age< (select avg(b.age) from student b)

D select * from student a where (select avg(b.age) from student b ) >= a.age

相似考题

1.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【 】。

2.根据SQL标准，删除表student中对字段sno的唯一性约束，应该使用下面哪条语句? ()A drop sno from table studentB alter table student drop snoC alter table student drop unique(sno)D alter table student drop sno unique

3.根据SQL标准，要修改表student中所有学生的年龄age，使之在原值基础上减一，下面哪个语句适用?()A update student set age = 1B update student set age = age - 1C update age = age -1 from studentD update from student where age = age -1

4.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)B select dept,avg(age) from student group by dept having avg(age)C select dept,avg(age) from student having avg(age)D select dept,avg(age) from student group by dept where avg(age)

参考答案和解析
参考答案C
更多“根据SQL标准,要查询表student中所有年龄age小于所有学生的平均年龄的记录,下面哪条语句适用?() ”相关问题

  • 第1题：

    根据SQL标准，增加一条记录到表student，学号sno是11301，姓名sname是“snoopy”，年龄age是20。其中student表中包括学号、姓名、年龄、籍贯、系别等属性，并且属性除sno外皆可取空值。下面哪条是参考的?()

    A insert into student values(sno=11301, sname=’snoopy’, age =20)

    B insert into student(sno,sname,age) values(11301,’snoopy’,20)

    C insert into student set sno=11301, sname=’snoopy’, age = 20

    D insert into student values (11301, ’snoopy’, 20)


    参考答案B

  • 第2题：

    根据SQL标准，要删除表student中所有数据，但不将表student的定义一起删除，下面哪个语句可以适用?()

    A delete from student

    B delete all from student

    C delete * from student

    D drop table student


    参考答案A

  • 第3题：

    根据SQL标准，查询表student(sno,sname,sex,dept)中所有学生的选修课程数，其中选修记录在表SC(sno,cno,grade)中，两表中sno为关联字段。下面哪条语句合适?()

    A select sno,count(cno) from SC

    B select sno,count(cno) from student

    C select a.sno,count(cno) from student a left outer join SC

    D select a.sno,count(cno) from SC left outer join student a


    参考答案C

  • 第4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)


    参考答案D

  • 第5题：

    根据SQL标准，下面哪条语句与select min(age) from student等效?()

    A select age from student where age >= min(age)

    B select distinct age from student where age >= all min(age)

    C select distinct a.age from student a where a.age<= any (select distinctb.age from student b)

    D select distinct a.age from student a where a.age<= all (select distinct b.age from student b)


    参考答案D

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