mysql 整型最大值_在SQL中如何获取整数的最大值？

在Mysql中有一个很便宜的手段：

mysql> select ~0;

+----------------------+

| ~0 |

+----------------------+

| 18446744073709551615 |

+----------------------+

对于其他整数风格,您可以使用正确的位移操作符>>像这样：

SELECT ~0 as max_bigint_unsigned,~0 >> 32 as max_int_unsigned,~0 >> 40 as max_mediumint_unsigned,~0 >> 48 as max_smallint_unsigned,~0 >> 56 as max_tinyint_unsigned,~0 >> 1 as max_bigint_signed,~0 >> 33 as max_int_signed,~0 >> 41 as max_mediumint_signed,~0 >> 49 as max_smallint_signed,~0 >> 57 as max_tinyint_signed

G

*************************** 1. row ***************************

max_bigint_unsigned: 18446744073709551615

max_int_unsigned: 4294967295

max_mediumint_unsigned: 16777215

max_smallint_unsigned: 65535

max_tinyint_unsigned: 255

max_bigint_signed: 9223372036854775807

max_int_signed: 2147483647

max_mediumint_signed: 8388607

max_smallint_signed: 32767

max_tinyint_signed: 127

1 row in set (0.00 sec)