A: DELETE Age from Student
B: UPDATE Student Age
C: ALTER TABLE Student(Age)
D: ALTER TABLE Student DROP Age
举一反三
- 用下面的语句创建了Student表:CREATE TABLE Student(Sno CHAR(10) primary key,Sname VARCHAR(10),age SMALLINT,Cname VARCHAR(20) );请用ALTER TABLE语句设置age字段默认值为20,正确的语句是()。 A: ALTER TABLE Student ALTER COLUMN age SET DEFAULT 20; B: ALTER TABLE Student CHANGE COLUMN age SET DEFAULT 20; C: ALTER TABLE Student ADD COLUMN age SET DEFAULT 20; D: ALTER TABLE Student DROP COLUMN age SET DEFAULT 20;
- 中国大学MOOC: 设已有关系Student(Sno, Sname, Sex, Age),若欲删除该表中的属性Age,恰当的SQL语句是( )。
- 学生表s有4个字段分别为:sno,sname,sex,age,要在表s中删除字段age,可选用的SQL语句是( )。 A: delete age from s; B: alter table s delete age; C: update s age; D: alter table s drop age;
- 学生表student中,将年龄小于30岁的记录删除,下面的语句正确的是( )。 A: DELETE FROM student FOR age<;30 B: DELETE FROM student WHERE age<;30 C: DELETE TABLE student WHERE age<;30 D: DELETE FROM student HAVING age<;30
- 若有关系St (NO,NAME,SEX,AGE),删除其中AGE字段的SQL语句是 ( )。 A: ALTER TABLE St DROP AGE B: DROP AGE FROM St C: ALTER TABLE St DELETE AGE D: DELETE AGE FROM St
内容
- 0
对于学生信息表:student(sno,sname,sex,age,dept),能够得到年龄在20岁至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
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关系模式:Student(Sno, Sname, Age),其中Sno、Sname、Age分别表示学生的学号、姓名和年龄。“查询年龄大于20岁的学生姓名”的关系代数表达式是() A: σSname(σage>20(Student)) B: ΠSname(σage>20(Student)) C: σSname(Πage>20(Student)) D: ΠSno(σage>20(Student))
- 2
若要删除基本表S中的Age列,应该选用的SQL语句是( )。 A: DELETE Age FROM S B: ALTER TABLE DROP Age C: UPDATE S Age D: ALTER TABLE S ‘Age’
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姓名、性别、年龄。要在表S中删除一个属性“年龄”,可选用的SQL语句是()。 A: UPDATE S Age B: DELETE Age from S C: ALTER TABLE S ‘Age’ D: ALTER TABLE S DROP Age
- 4
如果学生表STUDENT是使用下面的SQL语句创建的CREATE TABLE STUDENT( SNO varchar(4) PRIMARY KEY,SNAME varchar(8),SEX char(2),AGE int CHECK(AGE>15 AND AGE<30))则下面的语句中可以正确执行的是( )。 A: INSERT INTO STUDENT(SNO,SEX,AGE)values(‘S9’, ’男’, 17) B: INSERT INTO STUDENT(SNO,SEX,AGE)values(‘S9’, ‘男’, 14) C: INSERT INTO STUDENT(SNO,SEX,AGE)values(‘男’, 20) D: INSERT INTO STUDENT(SNO,SEX,AGE)values(‘S9’,‘安琦’, 16)