mysql创建表

temporary创建临时表 使用关键字temporary可以创建临时表。临时表只能对创建它的用户课件。临时表可以和持久表有同样的表明，此时临时表会隐藏持久表。 例如： 原始表数据： mysql select * from student;+--------+----------+---------+-----------+| stu_

temporary创建临时表

原始表数据：

mysql> select * from student;
+--------+----------+---------+-----------+
| stu_id | stu_name | stu_tel | stu_score |
+--------+----------+---------+-----------+
|      1 | a        |     151 |        60 |
|      2 | b        |     152 |        61 |
|      3 | c        |     153 |        62 |
|      4 | d        |     154 |        63 |
+--------+----------+---------+-----------+
4 rows in set (0.00 sec)

mysql> create temporary table student(
    -> stu_id          int,
    -> stu_name        varchar(5),
    -> stu_tel         int(5),
    -> stu_score       int(2)
    -> );
Query OK, 0 rows affected (0.14 sec)

查询表student：

mysql> select * from student;
Empty set (0.00 sec)

如果表已经存在时不能再创建永久表。可通过if not exists 判断是否存在
也可以通过if exists 判断并删除一个表。

create table if not exists  student(
stu_id          int,
stu_name        varchar(5),
stu_tel         int(5)，
stu_score       int(2)
);
drop table if exists student;

复制表

create table student1 like student；

复制表结构的同时复制数据，并更改列名

mysql> create table student1 as
    -> (select stu_id as id,stu_name as name,stu_tel as tel,stu_score as score 
    -> from student);
Query OK, 4 rows affected (0.22 sec)
Records: 4  Duplicates: 0  Warnings: 0

mysql> select * from student1;
+----+------+------+-------+
| id | name | tel  | score |
+----+------+------+-------+
|  1 | a    |  151 |    60 |
|  2 | b    |  152 |    61 |
|  3 | c    |  153 |    62 |
|  4 | d    |  154 |    63 |
+----+------+------+-------+
4 rows in set (0.00 sec)

mysql> create table student1(stu_id int primary key) as (select * from student);
Query OK, 4 rows affected (0.22 sec)
Records: 4  Duplicates: 0  Warnings: 0

其他参数：

auto_increment为新添加的行自动递增的分配一个id，也可设置递增分配id的起始id
default 为列设定默认值。
comment 为列添加说明

例：

create table student(
stu_id          int primary key auto_increment comment '学生ID',
stu_name        varchar(5) comment '学生姓名',
stu_tel         int(5) comment '学生电话',
stu_score       int(2) default 60 comment '学生成绩'
)auto_increment = 100;

mysql> insert into student values(NULL,'a',150,default);
Query OK, 1 row affected (0.03 sec)

mysql> select * from student;
+--------+----------+---------+-----------+
| stu_id | stu_name | stu_tel | stu_score |
+--------+----------+---------+-----------+
|    100 | a        |     150 |        60 |
+--------+----------+---------+-----------+
1 row in set (0.00 sec)

mysql> select column_name,column_comment
    -> from information_schema.columns
    -> where table_name = 'student';
+-------------+----------------+
| column_name | column_comment |
+-------------+----------------+
| stu_id      | 学生ID         |
| stu_name    | 学生姓名       |
| stu_tel     | 学生电话       |
| stu_score   | 学生成绩       |
+-------------+----------------+
4 rows in set, 0 warnings (0.33 sec)