​Required Storage and Range for Integer Types Supported by MySQL​

Type

Storage (Bytes)

Minimum Value Signed

Minimum Value Unsigned

Maximum Value Signed

Maximum Value Unsigned

​​TINYINT​​

1

​​-128​​

​​0​​

​​127​​

​​255​​

​​SMALLINT​​

2

​​-32768​​

​​0​​

​​32767​​

​​65535​​

​​MEDIUMINT​​

3

​​-8388608​​

​​0​​

​​8388607​​

​​16777215​​

​​INT​​

4

​​-2147483648​​

​​0​​

​​2147483647​​

​​4294967295​​

​​BIGINT​​

8

-2的63方 

​​0​​

2的63方-1

2的64方-1


TINYINT

TINYINT[(M)] [UNSIGNED] [ZEROFILL]

A very small integer. The signed range is ​​-128​​​ to ​​127​​​. The unsigned range is ​​0​​​ to ​​255​​.


SMALLINT

A small integer. The signed range is ​​-32768​​​ to ​​32767​​​. The unsigned range is ​​0​​​ to ​​65535​​.


MEDIUMINT

MEDIUMINT[(M)] [UNSIGNED] [ZEROFILL]

A medium-sized integer. The signed range is -8388608 to 8388607. The unsigned range is 0 to 16777215.


INT

​​​INT[(​​​M​​​)] [UNSIGNED] [ZEROFILL]​​​

A normal-size integer. The signed range is ​​-2147483648​​​ to ​​2147483647​​​. The unsigned range is ​​0​​​ to ​​4294967295.​​

INTEGER

​​​INTEGER[(​​​M​​​)] [UNSIGNED] [ZEROFILL]​​​

This type is a synonym for ​​​INT​​​.


BIGINT

​​​BIGINT[(​​​M​​​)] [UNSIGNED] [ZEROFILL]​​​

A large integer. The signed range is ​​-9223372036854775808​​​ to ​​9223372036854775807​​​. The unsigned range is ​​0​​​ to ​​18446744073709551615​​.

​​SERIAL​​

​​SERIAL​​​ is an alias for ​​BIGINT UNSIGNED NOT NULL AUTO_INCREMENT UNIQUE​​.

DEMO

create table serial_test (id SERIAL);

Int Data Type Syntax_主键

从图可知，是无符号的bigint类型，不能为空，主键，自动增长

1个表中，指定多个字段为serial，会报错(Incorrect table definition; there can be only one auto column and it must be defined as a key)


BOOL, BOOLEAN

These types are synonyms for ​​​TINYINT(1)​​​. A value of zero is considered false. Nonzero values are considered true.

0是fase，不为0是true