MySQL如何管理创建CREATE表和索引

发布时间：2021-11-11 15:20:06 来源：亿速云阅读：115 作者：小新栏目：数据库

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SQL语句：

数据库

表

索引

视图

DML语句

单字段：

PRIMARY KEY 主键

UNIQUE KEY 唯一键

单或者多字段：

PRIMARY KEY(col,...)

UNIQUE KEY(col,...)

INDEX(col,...)

数据类型：

data_type:

BIT[(length)] 比特

| TINYINT[(length)] [UNSIGNED] [ZEROFILL] 非常小的整数（1字节）

| SMALLINT[(length)] [UNSIGNED] [ZEROFILL]小的整数（2字节）

| MEDIUMINT[(length)] [UNSIGNED] [ZEROFILL]中等的整数（3字节）

| INT[(length)] [UNSIGNED] [ZEROFILL] 整数（4字节）

| INTEGER[(length)] [UNSIGNED] [ZEROFILL]整数（4字节）相当于INT

| BIGINT[(length)] [UNSIGNED] [ZEROFILL]大的整数（8个字节）

| REAL[(length,decimals)] [UNSIGNED] [ZEROFILL]实数

| DOUBLE[(length,decimals)] [UNSIGNED] [ZEROFILL]双数

| FLOAT[(length,decimals)] [UNSIGNED] [ZEROFILL]浮点型

| DECIMAL[(length[,decimals])] [UNSIGNED] [ZEROFILL]十进制小数点型

| NUMERIC[(length[,decimals])] [UNSIGNED] [ZEROFILL]数值型

| DATE 日期型

| TIME 时间型

| TIMESTAMP 时区型

| DATETIME 日期时间型

| YEAR 年

| CHAR[(length)] 定长字符型

VARCHAR(length)变长字符型

[CHARACTER SET charset_name] [COLLATE collation_name]

| BINARY[(length)]二进制数

| VARBINARY(length)变长二进制数

| TINYBLOB 非常小的大对数

| BLOB 大对数

| MEDIUMBLOB 中等的大对数

| LONGBLOB 长的大对数

| TINYTEXT [BINARY]非常小的文本串

[CHARACTER SET charset_name] [COLLATE collation_name]

| TEXT [BINARY]文本串

[CHARACTER SET charset_name] [COLLATE collation_name]

| MEDIUMTEXT [BINARY]中等的文本串

[CHARACTER SET charset_name] [COLLATE collation_name]

| LONGTEXT [BINARY]长的文本串

[CHARACTER SET charset_name] [COLLATE collation_name]

| ENUM(value1,value2,value3,...)枚举型

[CHARACTER SET charset_name] [COLLATE collation_name]

| SET(value1,value2,value3,...)集合型

[CHARACTER SET charset_name] [COLLATE collation_name]

| spatial_type 空间的类型

1、创建数据库：

CREATE DATABASE|SCHEMA [IF NOT EXISTS] db_name [CHARACTER SET=] [COLLATE]

创建数据库可以设置字符集，排序规则

mysql> SHOW CHARACTER SET; #查看字符集

+----------+-----------------------------+---------------------+--------+

+----------+-----------------------------+---------------------+--------+

.......

| big5 | Big5 Traditional Chinese | big5_chinese_ci | 2 |

| tis620 | TIS620 Thai | tis620_thai_ci | 1 |

| cp1250 | Windows Central European | cp1250_general_ci | 1 |

| gbk | GBK Simplified Chinese | gbk_chinese_ci | 2 |

| cp852 | DOS Central European | cp852_general_ci | 1 |

| cp1251 | Windows Cyrillic | cp1251_general_ci | 1 |

........

+----------+-----------------------------+---------------------+--------+

39 rows in set (0.00 sec)

mysql> SHOW COLLATION; #查看排序规则

+--------------------------+----------+-----+---------+----------+---------+

+--------------------------+----------+-----+---------+----------+---------+

| big5_chinese_ci | big5 | 1 | Yes | Yes | 1 |

| big5_bin | big5 | 84 | | Yes | 1 |

| cp1250_polish_ci | cp1250 | 99 | | Yes | 1 |

| gbk_chinese_ci | gbk | 28 | Yes | Yes | 1 |

| gbk_bin | gbk | 87 | | Yes | 1 |

| latin5_turkish_ci | latin5 | 30 | Yes | Yes | 1 |

+--------------------------+----------+-----+---------+----------+---------+

197 rows in set (0.00 sec)

mysql> CREATE DATABASE IF NOT EXISTS students CHARACTER SET 'gbk' COLLATE 'gbk_chinese_ci';

#创建一个students数据库，字符集为gbk，排序规则为gbk_chinese_ci

Query OK, 1 row affected (0.01 sec)

mysql> \q

Bye

[root@lamp ~]# ls /mydata/data #查看students是否新建成功

ib_logfile1 mysql-bin.000001 mysql-bin.000006 mysql-bin.000011 students

lamp.err mysql-bin.000002 mysql-bin.000007 mysql-bin.000012 test

[root@lamp ~]# file /mydata/data/students/db.opt #查看students数据库中db.opt文件类型

/mydata/data/students/db.opt: ASCII text

2、修改数据库：

ALTER {DATABASE | SCHEMA} [db_name] alter_specification ...#修改数据库的属性，比如字符集或者排序规则，alter_specification CHARACTER SET = charset_name COLLATE = collation_name

alter_specification包含:

[DEFAULT] CHARACTER SET [=] charset_name

| [DEFAULT] COLLATE [=] collation_name

ALTER {DATABASE | SCHEMA} db_name UPGRADE DATA DIRECTORY NAME #升级数据库的数据目录

3、删除数据库：

DROP {DATABASE | SCHEMA} [IF EXISTS] db_name #删除数据库

4、创建表：

1.直接定义一张空表；col_name 字段名称 col_defination 字段定义

CREATE TABLE [IF NOT EXISTS] tb_name (col_name col_defination,)

col_defination字段定义包含：data_type字段类型

data_type [NOT NULL | NULL] [DEFAULT default_value]

[AUTO_INCREMENT] [UNIQUE [KEY] | [PRIMARY] KEY]

[COMMENT 'string']

[COLUMN_FORMAT {FIXED|DYNAMIC|DEFAULT}]

[STORAGE {DISK|MEMORY|DEFAULT}]

[reference_definition]

Usage:CREATE TABLE tb1(id INT UNSIGNED NOT NULL AUTO_INCREMENT PRIMARY KEY,Name CHAR(20) NOT NULL,Age TINYINT NOT NULL);#创建一个表tb1，包含三个字段:id字段为无符号(UNSIGNED)，非空(NOT NULL)，自动增长(AUTO_INCREMENT)，为主键(PRIMARY KEY)的整型.Name字段为定长20(CHAR(20)),非空的字符型。Age字段为非空的非常小的整型。

或者 CREATE TABLE tb2(id INT UNSIGNED NOT NULL AUTO_INCREMENT,Name CHAR(20) NOT NULL,Age TINYINT NOT NULL,PRIMARY KEY(id),Unique KEY (Name),INDEX(age)); Unique KEY 唯一键，INDEX索引

2.从其他表中查询出数据，并以之创建新表；

CREATE TABLE testcourses SELECT * FROM courses WHERE CID <= 2;#从courses表中查找

CID小于等于2的数据，并作为新建testcourses表的内容。

3.以其他表为模板创建一个空表；

CREATE TABLE new_table LIKE old_table; 以old_table表为模板，建立new_table表

查看表索引：

SHOW INDEXES FROM courses; 显示制定表索引

查看表结构：

DESC tb_name; 查看表结构

mysql> DESC courses;

+-------+---------------------+------+-----+---------+----------------+

+-------+---------------------+------+-----+---------+----------------+

| CID | tinyint(3) unsigned | NO | PRI | NULL | auto_increment |

+-------+---------------------+------+-----+---------+----------------+

2 rows in set (0.00 sec)

5、修改表定义：ALTER TABLE

添加、删除、修改字段，添加、删除、修改索引，改表名，修改表属性。

mysql> ALTER TABLE test ADD INDEX(Couse); #给test表增加以Couse字段为索引

Query OK, 0 rows affected (0.01 sec)

Records: 0 Duplicates: 0 Warnings: 0

mysql> SHOW INDEXES FROM test; #查看test表的索引

+-------+------------+----------+--------------+-------------+-----------+-------------+----------+--------+------+------------+---------+---------------+

+-------+------------+----------+--------------+-------------+-----------+-------------+----------+--------+------+------------+---------+---------------+

| test | 0 | PRIMARY | 1 | CID | A | 0 | NULL | NULL | | BTREE | | |

+-------+------------+----------+--------------+-------------+-----------+-------------+----------+--------+------+------------+---------+---------------+

2 rows in set (0.00 sec)

mysql> DESC test; #查看表结构

+-------+---------------------+------+-----+---------+----------------+

+-------+---------------------+------+-----+---------+----------------+

| CID | tinyint(3) unsigned | NO | PRI | NULL | auto_increment |

+-------+---------------------+------+-----+---------+----------------+

2 rows in set (0.00 sec)

mysql> ALTER TABLE test CHANGE Couse Course VARCHAR(50) NOT NULL; #修改test表的Couse字段名称为Course并定义为变长50字符长度，非空

Query OK, 0 rows affected (0.01 sec)

Records: 0 Duplicates: 0 Warnings: 0

mysql> DESC test; 查看表结构

+--------+---------------------+------+-----+---------+----------------+

+--------+---------------------+------+-----+---------+----------------+

| CID | tinyint(3) unsigned | NO | PRI | NULL | auto_increment |

+--------+---------------------+------+-----+---------+----------------+

2 rows in set (0.00 sec)

mysql> DROP TABLE testcourses; #删除testcourses表

Query OK, 0 rows affected (0.00 sec)

mysql> SHOW TABLES;查看所有表

+--------------------+

| Tables_in_students |

+--------------------+

| courses |

| test |

+--------------------+

2 rows in set (0.00 sec)

mysql> ALTER TABLE test RENAME TO testcourses; #修改test表的名称为testcourses

Query OK, 0 rows affected (0.00 sec)

mysql> SHOW TABLES;查看所有表

+--------------------+

| Tables_in_students |

+--------------------+

| courses |

| testcourses |

+--------------------+

2 rows in set (0.00 sec)

mysql> RENAME TABLE testcourses TO test; #也可以直接使用RENAME重命名。

Query OK, 0 rows affected (0.00 sec)

6、新增索引：（索引只能新建删除，不能修改）

CREATE INDEX index_name ON tb_name (col,...)

col_name (length) ASC|DESC 指定以字段前几的长度为索引，ASC升序排列，

DESC降序排列。

在tb_name表上的col字段创建一个索引index_name

CREATE INDEX name_on_student ON student (Name) USING BTREE;

#在student表中Name字段上建立一个名为name_on_student索引，类型为BTREE索引，默认为BTREE类型。

mysql> CREATE INDEX name_on_student ON student (Name) USING BTREE ;

Query OK, 0 rows affected (0.15 sec)

Records: 0 Duplicates: 0 Warnings: 0

mysql> SHOW INDEXES FROM student ;

+---------+------------+-----------------+--------------+-------------+-----------+-------------+----------+--------+------+------------+---------+---------------+

+---------+------------+-----------------+--------------+-------------+-----------+-------------+----------+--------+------+------------+---------+---------------+

| student | 0 | PRIMARY | 1 | SID | A | 4 | NULL | NULL | | BTREE | | |

| student | 1 | foreign_cid | 1 | CID | A | 4 | NULL | NULL | | BTREE | | |

| student | 1 | name_on_student | 1 | Name | A | 4 | NULL | NULL | YES | BTREE | | |

+---------+------------+-----------------+--------------+-------------+-----------+-------------+----------+--------+------+------------+---------+---------------+

3 rows in set (0.00 sec)

mysql> DROP INDEX name_on_student ON student;#删除student表中的索引name_on_student

Query OK, 0 rows affected (0.04 sec)

Records: 0 Duplicates: 0 Warnings: 0

mysql> CREATE INDEX name_on_student ON student (Name(5) DESC);#为student表以Name字段

的前5个字符建立一个降序（DESC）排列的索引.

Query OK, 0 rows affected (0.05 sec)

Records: 0 Duplicates: 0 Warnings: 0

实例1：创建一个students数据库，以及表的创建，查找等功能的练习；

mysql> CREATE DATABASE IF NOT EXISTS students CHARACTER SET 'gbk' COLLATE 'gbk_chinese_ci';

#创建一个students数据库，字符集为gbk，排序规则为gbk_chinese_ci

Query OK, 1 row affected (0.01 sec)

mysql> USE students;

Database changed

mysql> CREATE TABLE courses(CID TINYINT UNSIGNED NOT NULL AUTO_INCREMENT PRIMARY KEY,Couse VARCHAR(50) NOT NULL);

Query OK, 0 rows affected (0.07 sec)

mysql> SHOW TABLE STATUS LIKE 'courses'\G;

*************************** 1. row ***************************

Name: courses

Engine: InnoDB

Version: 10

Row_format: Compact

Rows: 0

Avg_row_length: 0

Data_length: 16384

Max_data_length: 0

Index_length: 0

Data_free: 0

Auto_increment: 1

Create_time: 2017-04-25 10:19:13

Update_time: NULL

Check_time: NULL

Collation: gbk_chinese_ci

Checksum: NULL

Create_options:

Comment:

1 row in set (0.00 sec)

ERROR:

No query specified

mysql> DROP TABLES courses; #删除表

Query OK, 0 rows affected (0.01 sec)

mysql> CREATE TABLE courses(CID TINYINT UNSIGNED NOT NULL AUTO_INCREMENT PRIMARY KEY,Couse VARCHAR(50) NOT NULL) ENGINE=MyISAM; #ENGINE设定引擎为MyISAM

Query OK, 0 rows affected (0.00 sec)

mysql> SHOW TABLE STATUS LIKE 'courses'\G;

*************************** 1. row ***************************

Name: courses

Engine: MyISAM

Version: 10

Row_format: Dynamic

Rows: 0

Avg_row_length: 0

Data_length: 0

Max_data_length: 281474976710655

Index_length: 1024

Data_free: 0

Auto_increment: 1

Create_time: 2017-04-25 10:51:45

Update_time: 2017-04-25 10:51:45

Check_time: NULL

Collation: gbk_chinese_ci

Checksum: NULL

Create_options:

Comment:

1 row in set (0.00 sec)

ERROR:

No query specified

mysql> INSERT INTO courses (Couse) values ('physics'),('english'),('chemistry'),('maths');

#插入Couse课程字段数据，添加物理，英语，化学，数学等课程。

Query OK, 4 rows affected (0.00 sec)

Records: 4 Duplicates: 0 Warnings: 0

mysql> SELECT * FROM courses; #查询courses表的条目

+-----+-----------+

| CID | Couse |

+-----+-----------+

| 1 | physics |

| 2 | english |

| 3 | chemistry |

| 4 | maths |

+-----+-----------+

4 rows in set (0.00 sec)

mysql> SHOW INDEXES FROM courses; #查看courses表的索引

+---------+------------+----------+--------------+-------------+-----------+-------------+----------+--------+------+------------+---------+---------------+

+---------+------------+----------+--------------+-------------+-----------+-------------+----------+--------+------+------------+---------+---------------+

| courses | 0 | PRIMARY | 1 | CID | A | 4 | NULL | NULL | | BTREE | | |

+---------+------------+----------+--------------+-------------+-----------+-------------+----------+--------+------+------------+---------+---------------+

1 row in set (0.00 sec)

mysql> CREATE TABLE testcourses SELECT * FROM courses WHERE CID <= 2; #查找courses表中CID字段小于等于2的数据，并把查找到的数据作为新建testcourses表的数据内容。

Query OK, 2 rows affected (0.08 sec)

Records: 2 Duplicates: 0 Warnings: 0

mysql> SHOW TABLES; #查看当前数据库表的信息

+--------------------+

| Tables_in_students |

+--------------------+

| courses |

| testcourses |

+--------------------+

2 rows in set (0.00 sec)

mysql> SELECT * FROM testcourses; #查看testcourses表的内容

+-----+---------+

| CID | Couse |

+-----+---------+

| 1 | physics |

| 2 | english |

+-----+---------+

2 rows in set (0.00 sec)

mysql> DESC courses; #查看courses表结构

+-------+---------------------+------+-----+---------+----------------+

+-------+---------------------+------+-----+---------+----------------+

| CID | tinyint(3) unsigned | NO | PRI | NULL | auto_increment |

+-------+---------------------+------+-----+---------+----------------+

2 rows in set (0.00 sec)

mysql> DESC testcourses; #查看testcourses表结构

+-------+---------------------+------+-----+---------+-------+

+-------+---------------------+------+-----+---------+-------+

| CID | tinyint(3) unsigned | NO | | 0 | |

+-------+---------------------+------+-----+---------+-------+

2 rows in set (0.00 sec)

mysql> CREATE TABLE test LIKE courses; #以courses表为模板创建test空表。

Query OK, 0 rows affected (0.00 sec)

mysql> DESC test; #查看test表结构

+-------+---------------------+------+-----+---------+----------------+

+-------+---------------------+------+-----+---------+----------------+

| CID | tinyint(3) unsigned | NO | PRI | NULL | auto_increment |

+-------+---------------------+------+-----+---------+----------------+

2 rows in set (0.00 sec)

mysql> SHOW TABLE STATUS LIKE 'test'\G; #查看test表的状态

*************************** 1. row ***************************

Name: test

Engine: MyISAM

Version: 10

Row_format: Dynamic

Rows: 0

Avg_row_length: 0

Data_length: 0

Max_data_length: 281474976710655

Index_length: 1024

Data_free: 0

Auto_increment: 1

Create_time: 2017-04-25 11:31:46

Update_time: 2017-04-25 11:31:46

Check_time: NULL

Collation: gbk_chinese_ci

Checksum: NULL

Create_options:

Comment:

1 row in set (0.00 sec)

ERROR:

No query specified

实例2.建立student表，并进行相关数据的插入，查询操作练习，修改引擎，修改字段修饰，

增加外键索引；

mysql> CREATE TABLE student (SID INT UNSIGNED NOT NULL AUTO_INCREMENT PRIMARY KEY,Name

VARCHAR(30),CID INT NOT NULL);#创建student表，包含3个字段，SID字段为无符号非空自动增长主键的整数型，Name字段为变长30字符，CID字符为非空整数型。

mysql> SHOW TABLES;

+--------------------+

| Tables_in_students |

+--------------------+

| courses |

| student |

| test |

+--------------------+

3 rows in set (0.00 sec)

mysql> INSERT INTO student (Name,CID) VALUES ('Li Lianjie',1),('Cheng Long',2);#对Name,CID字段插入2条数据。

Query OK, 2 rows affected (0.01 sec)

Records: 2 Duplicates: 0 Warnings: 0

mysql> SELECT * FROM student; #查询student表

+-----+------------+-----+

| SID | Name | CID |

+-----+------------+-----+

| 1 | Li Lianjie | 1 |

| 2 | Cheng Long | 2 |

+-----+------------+-----+

2 rows in set (0.00 sec)

mysql> SELECT * FROM courses;#查询courses表

+-----+-----------+

| CID | Couse |

+-----+-----------+

| 1 | physics |

| 2 | english |

| 3 | chemistry |

| 4 | maths |

+-----+-----------+

4 rows in set (0.00 sec)

mysql> SELECT Name,Couse FROM student,courses WHERE student.CID=courses.CID; #查询student表和courses表中CID相同的Name和Couse字段内容

+------------+---------+

| Name | Couse |

+------------+---------+

| Li Lianjie | physics |

| Cheng Long | english |

+------------+---------+

2 rows in set (0.00 sec)

mysql> DELETE FROM student WHERE SID > 5; 删除SID大于5的行。

Query OK, 5 rows affected (0.01 sec)

mysql> ALTER TABLE courses ENGINE=Innodb; #修改courses表的引擎为Innodb;

Query OK, 4 rows affected (0.03 sec)

Records: 4 Duplicates: 0 Warnings: 0

mysql> ALTER TABLE student MODIFY CID TINYINT UNSIGNED NOT NULL;#修改student表中CID字段的修饰（MODIFY）。

Query OK, 4 rows affected (0.02 sec)

Records: 4 Duplicates: 0 Warnings: 0

mysql> DESC courses;

+-------+---------------------+------+-----+---------+----------------+

+-------+---------------------+------+-----+---------+----------------+

| CID | tinyint(3) unsigned | NO | PRI | NULL | auto_increment |

+-------+---------------------+------+-----+---------+----------------+

2 rows in set (0.00 sec)

mysql> DESC student;

+-------+---------------------+------+-----+---------+----------------+

+-------+---------------------+------+-----+---------+----------------+

| SID | int(10) unsigned | NO | PRI | NULL | auto_increment |

| CID | tinyint(3) unsigned | NO | | NULL | |

+-------+---------------------+------+-----+---------+----------------+

3 rows in set (0.00 sec)

mysql> ALTER TABLE student ADD FOREIGN KEY foreign_cid (CID) REFERENCES courses (CID);

为student表的CID字段增加一个外键foreign_cid关联courses表的CID字段。

Query OK, 4 rows affected (0.03 sec)

Records: 4 Duplicates: 0 Warnings: 0

mysql> SHOW INDEXES FROM student; 查看student表的索引

+---------+------------+-------------+--------------+-------------+-----------+-------------+----------+--------+------+------------+---------+---------------+

+---------+------------+-------------+--------------+-------------+-----------+-------------+----------+--------+------+------------+---------+---------------+

| student | 0 | PRIMARY | 1 | SID | A | 2 | NULL | NULL | | BTREE | | |

| student | 1 | foreign_cid | 1 | CID | A | 2 | NULL | NULL | | BTREE | | |

+---------+------------+-------------+--------------+-------------+-----------+-------------+----------+--------+------+------------+---------+---------------+

2 rows in set (0.00 sec)

mysql> INSERT INTO student (Name,CID) VALUES ('Guo Xiang',5);

ERROR 1452 (23000): Cannot add or update a child row: a foreign key constraint fails (`students`.`student`, CONSTRAINT `student_ibfk_1` FOREIGN KEY (`CID`) REFERENCES `courses` (`CID`)) #提示报错，由于CID外键索引courses表中CID没有5，所以无法增加。

mysql> ALTER TABLE student AUTO_INCREMENT=5;#设定student表下一条数据的自动增长主键SID

从5开始增长。

Query OK, 4 rows affected (0.05 sec)

Records: 4 Duplicates: 0 Warnings: 0

mysql> SELECT * FROM student;#查询表的内容

+-----+-------------+-----+

| SID | Name | CID |

+-----+-------------+-----+

| 1 | Li Lianjie | 1 |

| 2 | Cheng Long | 2 |

| 3 | Xiao Longnv | 3 |

| 4 | Yang Guo | 4 |

+-----+-------------+-----+

4 rows in set (0.00 sec)

mysql> INSERT INTO student (Name,CID) VALUES ('Guo Xiang',3);#插入一条数据，SID主键由于上面设置从5开始增长，所以刚插入的数据是从5开始；

Query OK, 1 row affected (0.00 sec)

mysql> SELECT * FROM student;

+-----+-------------+-----+

| SID | Name | CID |

+-----+-------------+-----+

| 1 | Li Lianjie | 1 |

| 2 | Cheng Long | 2 |

| 3 | Xiao Longnv | 3 |

| 4 | Yang Guo | 4 |

| 5 | Guo Xiang | 3 |

+-----+-------------+-----+

5 rows in set (0.00 sec)

mysql> INSERT INTO student (Name,CID) VALUES ('Qiao Feng',2);插入数据

Query OK, 1 row affected (0.00 sec)

mysql> SELECT * FROM student;

+-----+-------------+-----+

| SID | Name | CID |

+-----+-------------+-----+

| 1 | Li Lianjie | 1 |

| 2 | Cheng Long | 2 |

| 3 | Xiao Longnv | 3 |

| 4 | Yang Guo | 4 |

| 5 | Guo Xiang | 3 |

| 6 | Qiao Feng | 2 |

+-----+-------------+-----+

6 rows in set (0.00 sec)

mysql> DELETE FROM student WHERE SID >2 AND SID <5; #删除2<SID<5的行

Query OK, 2 rows affected (0.00 sec)

mysql> SELECT * FROM student;

+-----+------------+-----+

| SID | Name | CID |

+-----+------------+-----+

| 1 | Li Lianjie | 1 |

| 2 | Cheng Long | 2 |

| 5 | Guo Xiang | 3 |

| 6 | Qiao Feng | 2 |

+-----+------------+-----+

4 rows in set (0.00 sec)

mysql> DELETE FROM student WHERE SID in (5,6); #删除SID为5和6的行

Query OK, 2 rows affected (0.00 sec)

mysql> SELECT * FROM student;

+-----+------------+-----+

| SID | Name | CID |

+-----+------------+-----+

| 1 | Li Lianjie | 1 |

| 2 | Cheng Long | 2 |

+-----+------------+-----+

2 rows in set (0.00 sec)

mysql> ALTER TABLE student AUTO_INCREMENT=3; #设定student表下一条数据的自动增长主键

SID从3开始增长。

Query OK, 2 rows affected (0.07 sec)

Records: 2 Duplicates: 0 Warnings: 0

mysql> INSERT INTO student (Name,CID) VALUES ('Yang Guo',3),('Guo Jing',4);#插入2条数据

Query OK, 2 rows affected (0.00 sec)

Records: 2 Duplicates: 0 Warnings: 0

mysql> SELECT * FROM student;

+-----+------------+-----+

| SID | Name | CID |

+-----+------------+-----+

| 1 | Li Lianjie | 1 |

| 2 | Cheng Long | 2 |

| 3 | Yang Guo | 3 |

| 4 | Guo Jing | 4 |

+-----+------------+-----+

4 rows in set (0.00 sec)

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MySQL如何管理创建CREATE表和索引

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