MySQL中数据类型详解
1、数值类型：
BIT[(M)]
二进制位,M指定值的位数,从1到64(也就是说它能定义任意的介于1到64位之间的整数),如某字段的类型定义为BIT或BIT[1],它就只能取0或1,定义为BIT[2]只能取0~3之间的整数,如果没有指定M则默认M=1.
TINYINT[(M)] [UNSIGNED] [ZEROFILL]
8位整数,有符号数的取值范围是-128到127,无符号数的取值范围是0到255(此处M的取值范围是0到255,是用来控制显示宽度的,但实际上好像没用,区别BIT(M).)
BOOL,BOLLEAN
与TINYINT(1)同义.零被认为是false,非零数被认为是true.
SMALLINT[(M)] [UNSIGNED] [ZEROFILL]
16位整数,有符号数的取值范围为-32768到32767,无符号数的取值范围是0到65535.
MEDIUMINT[(M)] [UNSIGNED] [ZEROFILL]
24位整数,有符号数取值范围是-8388608到8388607,无符号数的取值范围是0到16777215.
INT[(M)] [UNSIGNED] [ZEROFILL]
32位整数,有符号数的取值范围是-2147483648到2147483647,无符号数的取值范围是0到4294967295.
INTERGER[(M)] [UNSIGNED] [ZEROFILL]
同INT.
BIGINT[(M)] [UNSIGNED] [ZEROFILL]
64位整数,有符号数的取值范围是-9223372036854775808到9223372036854775807,无符号的取值范围是0到18446744073709551615.
二、日期和时间类型
三、字符(串)类型
English from MySQL 5.0 Reference Manual:
1. Overview of Numeric Types
BIT[( M)]
A bit-field type. M indicates the number of bits per value, from 1 to 64. The default is 1 if M is omitted.
This data type was added in MySQL 5.0.3 for MyISAM, and extended in 5.0.5 to MEMORY, InnoDB, and BDB. Before 5.0.3, BIT is a synonym for TINYINT(1).
TINYINT[( M)] [UNSIGNED] [ZEROFILL]
A very small integer. The signed range is -128 to 127. The unsigned range is 0 to 255.
BOOL, BOOLEAN
These types are synonyms for TINYINT(1). A value of zero is considered false. Non-zero values are considered true.
In the future, full boolean type handling will be introduced in accordance with standard SQL.
SMALLINT[( M)] [UNSIGNED] [ZEROFILL]
A small integer. The signed range is -32768 to 32767. The unsigned range is 0 to 65535.
MEDIUMINT[( M)] [UNSIGNED] [ZEROFILL]
A medium-sized integer. The signed range is -8388608 to 8388607. The unsigned range is 0 to 16777215.
INT[( M)] [UNSIGNED] [ZEROFILL]
A normal-size integer. The signed range is -2147483648 to 2147483647. The unsigned range is 0 to 4294967295.
INTEGER[( M)] [UNSIGNED] [ZEROFILL]
This type is a synonym for INT.
BIGINT[( M)] [UNSIGNED] [ZEROFILL]
A large integer. The signed range is -9223372036854775808 to 9223372036854775807. The unsigned range is 0 to 18446744073709551615.