MySQL使用一个语句就可以查出各种整形占用字节数及最大最小值的示例代码-tutorial mysql-php.cn

MySQL使用一个语句就可以查出各种整形占用字节数及最大最小值的示例代码

黄舟

Lepaskan： 2017-03-21 13:26:09

asal

1237 orang telah melayarinya

下面小编就为大家带来一篇MySQL一个语句查出各种整形占用字节数及最大最小值的实例。

直接上码：

select &#39;bigint unsigned&#39; as type ,&#39;8&#39; as bytes ,~0 as max_num,0 as min_num union
select &#39;int unsigned&#39;,&#39;4&#39;,~0>>32,0 union
select &#39;mediumint unsigned&#39;,&#39;3&#39;,~0>>40,0 union
select &#39;smallint unsigned&#39;,&#39;2&#39;,~0>>48,0 union
select &#39;tinyint unsigned&#39;,&#39;1&#39;,~0>>56,0 union
select &#39;signed bigint&#39;,&#39;8&#39;,~0>>1,-(1<<63) union
select &#39;signed int&#39;,&#39;4&#39;,~0>>33,-(1<<31) union
select &#39;signed mediumint&#39;,&#39;3&#39;,~0>>41,-(1<<23) union
select &#39;signed smallint&#39;,&#39;2&#39;,~0>>49,-(1<<15) union
select &#39;signed tinyint&#39;,&#39;1&#39;,~0>>57,-(1<<7);

+--------------------+-------+----------------------+----------------------+
| type    | bytes | max_num    | min_num    |
+--------------------+-------+----------------------+----------------------+
| bigint unsigned | 8  | 18446744073709551615 |     0 |
| int unsigned  | 4  |   4294967295 |     0 |
| mediumint unsigned | 3  |    16777215 |     0 |
| smallint unsigned | 2  |    65535 |     0 |
| tinyint unsigned | 1  |     255 |     0 |
| signed bigint  | 8  | 9223372036854775807 | -9223372036854775808 |
| signed int   | 4  |   2147483647 |   -2147483648 |
| signed mediumint | 3  |    8388607 |    -8388608 |
| signed smallint | 2  |    32767 |    -32768 |
| signed tinyint  | 1  |     127 |     -128 |
+--------------------+-------+----------------------+----------------------+
rows in set (0.00 sec)

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