MySQL tinyint/smallint/int/bigint

MySQL tinyint/smallint/int/bigint取值范围

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数据类型	存储大小	取值范围	最大存储位数
tinyint	1 字节	signed : -128 ~ 127	3位
		unsigned : 0 ~ 255	3位
smallint	2 字节	signed : -32768 ~ 32767	5位
		unsigned : 0 ~ 65535	5位
int	4 字节	signed : -2147483648 ~ 2147483647	10位
		unsigned : 0 ~ 4294967295	10位
bigint	8 字节	signed : -9223372036854775808 ~ 9223372036854775807	19位
		unsigned : 0 ~ 18446744073709551615	20位

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    mysql> help tinyint;

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

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    mysql> help smallint;

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

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    mysql> help int;

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

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    mysql> help bigint;

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

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