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( )。
A: DELETE Age from Student
B: UPDATE Student Age
C: ALTER TABLE Student(Age)
D: ALTER TABLE Student DROP Age
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