mysql tinyint(1) vs tinyint(2) vs tinyint(3) vs tinyint(4)
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mysql tinyint(1) vs tinyint(2) vs tinyint(3) vs tinyint(4)
提问by Tarun Gupta
Possible Duplicate:
MySql: Tinyint (2) vs tinyint(1) - Which difference?
What is the difference between:
有什么区别：
TinyINT(1)TinyINT(2)TinyINT(3)TinyINT(4)
TinyINT(1)TinyINT(2)TinyINT(3)TinyINT(4)
回答by muehlbau
TinyINT(M) always has a range from -128..+127 signed or 0..255 unsigned. M is the display width.
TinyINT(M) 的范围始终为 -128..+127 有符号或 0..255 无符号。M 是显示宽度。
M indicates the maximum display width for integer types. The maximum display width is 255. Display width is unrelated to the range of values a type can contain, as described in Section 11.2, “Numeric Types”. For floating-point and fixed-point types, M is the total number of digits that can be stored.
M 表示整数类型的最大显示宽度。最大显示宽度为 255。显示宽度与类型可以包含的值范围无关，如第 11.2 节“数字类型”中所述。对于浮点和定点类型，M 是可以存储的总位数。
from http://dev.mysql.com/doc/refman/5.5/en/numeric-type-overview.html
来自http://dev.mysql.com/doc/refman/5.5/en/numeric-type-overview.html
回答by Vyktor
According to Mysql manualall decimal numeric types supports syntax:
根据Mysql 手册，所有十进制数字类型都支持语法：
Integer Types (Exact Value)
When using DECIMALit allows you to specify precision.
使用DECIMAL它时，您可以指定 precision。
With *INTtypes it's has mainly display functionwhich also specifies how many places should be added when using ZEROFILL.
对于*INT类型，它主要具有显示功能，该功能还指定使用ZEROFILL.
The byte size remains unaffected (1Bfor TINYINT).
字节大小不受影响（1BforTINYINT）。
回答by Francois
TinyINT = -128...+127
TinyINT = -128...+127
(n) is for display purposes.
(n) 用于显示目的。
