Mysqlには、これを行うための安価なトリックがあります：
mysql> select ~0;
+----------------------+
| ~0 |
+----------------------+
| 18446744073709551615 |
+----------------------+
チルダはビット単位の否定です。結果の値はbigintです。参照： http：//dev.mysql .com / doc / refman / 5.1 / en / bit-functions.html＃operator_bitwise-invert
その他の整数フレーバーについては、適切なビットシフト演算子>>を使用できます。 そのように：
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)