mysql 创建、修改、删除表_mysql create or replace table

1.主键设置在中间，在末尾都可以，例如：

mysql> CREATE TABLE example4 (
stu_id integer,
grade float,
stu_name varchar(100),
primary key(stu_id,stu_name),
favourite text );
 
Query OK, 0 rows affected (0.02 sec)

2.varchar 类型必须指明长度，否则会报错，例如：

CREATE TABLE example3
( 
stu_id int, 
grade float,
stu_name varchar,
favourite text,
primary key(stu_id,stu_name)
);
ERROR 1064 (42000): You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near ', favourite text,primary key(stu_id,stu_name))' at line 1

3.