MySQL table creation statement_Three commonly used MySQL table creation statements

The MySQL table creation statement is one of the most basic SQL statements. Here are the three most commonly used MySQL table creation statements. If you are interested in MySQL table creation statements, you may wish to take a look.

1. The simplest:

CREATE TABLE t1(

id int not null,

name char(20)

);

2. With primary key:

CREATE TABLE t1(

id int not null primary key,

name char(20)

);

b: Composite primary key

CREATE TABLE t1(

id int not null,

name char(20),

primary key (id,name)

);

3. With default value:

CREATE TABLE t1(

id int not null default 0 primary key,

name char(20) default '1'

);

Complete example:

DROP TABLE IF EXISTS `user_t`;

CREATE TABLE `user_t` (

`id` int(11) NOT NULL AUTO_INCREMENT,

`user_name` varchar(40) NOT NULL,

`password` varchar(255) NOT NULL,

`age` int(4) NOT NULL,

PRIMARY KEY (`id`)

) ENGINE=InnoDB AUTO_INCREMENT=2 DEFAULT CHARSET=utf8;

/*Data for the table `user_t` */

insert into `user_t`(`id`,`user_name`,`password`,`age`) values ​​(1,'test','sfasgfaf',24);

Explanation::

ENGINE=InnoDB uses the innodb storage engine

DEFAULT CHARSET=utf8 The default encoding of the database is utf-8

AUTO_INCREMENT=1 The starting sequence number of the auto-increment key is 1

Extension:

1. InnoDB is one of MySQL's database engines, and one of the standards for the release of binary for MySQL AB. InnoDB supports advanced functions such as transaction processing and foreign keys.

2.AUTO_INCREMENT generates a unique number when a new record is inserted into the table.If you want to automatically create the value of the primary key field every time a new record is inserted, you can create an auto-increment field in the table.
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Original link: https://blog.csdn.net/weixin_33582089/article/details/113112792