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
A delete from student
B delete all from student
C delete * from student
D drop table student
第1题
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 student
B alter table student drop sno
C alter table student drop unique(sno)
D alter table student drop sno unique
第2题
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 = 1
B update student set age = age - 1
C update age = age -1 from student
D update from student where age = age -1
第3题
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4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
第5题
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)
第6题
A insert into student sdate char(7)
B add sdate char(7) to student
C append sdate varchar(7) to table student
D alter table student add sdate varchar(7)
E alter table student add sdate char(7)
F alter table student modify sdate char(7)
第7题
根据SQL标准,删除一个表中的记录,下面哪个语句适用?()
A DROP TABLE
B DROP
C DELETE
D ERASE
第8题
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)
第9题
根据SQL标准,删除一个表,应该使用下面哪个语句?()
A DELETE TABLE
B DROP TABLE
C DELETE VIEW
D DROP DATABASE
第10题
A、DROP SCHEMA命令
B、DROP TABLE命令
第11题
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