mysql tinyint(1)vs tinyint(2)vs tinyint(3)vs tinyint(4) [英] mysql tinyint(1) vs tinyint(2) vs tinyint(3) vs tinyint(4)
问题描述
Possible Duplicate:
MySql: Tinyint (2) vs tinyint(1) - Which difference?
两者之间有什么区别
-
TinyINT(1) -
TinyINT(2) -
TinyINT(3) -
TinyINT(4)
TinyINT(1)TinyINT(2)TinyINT(3)TinyINT(4)
推荐答案
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.
TinyINT(M) always has a range from -128..+127 signed or 0..255 unsigned. M is the display width.
M表示整数类型的最大显示宽度.最大值 显示宽度为255.显示宽度与以下范围无关 类型可以包含的值，如第11.2节数字"中所述 类型".对于浮点和定点类型，M为总数 可存储的位数.
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.
来自 http://dev.mysql.com /doc/refman/5.5/en/numeric-type-overview.html
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