sql期末考试试题及答案

mysql>create table Score

->(Sno char(10),Cno char(10),Grade real,

->constraint pk foreign key(Sno)

->references student(Sno),

->constraint pk1 foreign key(Cno)

->references Course(Cno))

Query OK, 0 rows affected (0.01 sec)

2．增加、修改和删除字段，要求：

（1）给Student表增塌塌加一个memo(备注)字段，类型为Varchar(200)

mysql>alter table student add memo varchar(200)

Query OK, 0 rows affected (0.25 sec)

Records: 0 Duplicates: 0 Warnings: 0

（拍笑2）将memo字段的类型修改为袭衫含Varchar(300)

mysql>alter table student

->modify memo varchar(300)

Query OK, 0 rows affected (0.06 sec)

（3）删除memo 字段

mysql>alter table student drop memo

Query OK, 0 rows affected (0.02 sec)

我答帆弊案不保证全对啊