MySQL utilise une seule instruction pour connaître le nombre d'octets occupés par différents entiers ainsi que les valeurs maximales et minimales.

select 'bigint unsigned' as type ,'8' as bytes ,~0 as max_num,0 as min_num union
select 'int unsigned','4',~0>>32,0 union
select 'mediumint unsigned','3',~0>>40,0 union
select 'smallint unsigned','2',~0>>48,0 union
select 'tinyint unsigned','1',~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)