BINARY(n) ,varBINARY(n)： N代表字节数

utf8:

mysql> CREATE TABLE t (c BINARY());

Query OK,  rows affected (0.04 sec)

mysql> INSERT INTO t SET c = 'a';

Query OK,  row affected (0.19 sec)

mysql> SELECT HEX(c), c = 'a', c = 'a\0\0' from t;

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

| HEX(c) | c = 'a' | c = 'a\0\0' |

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

|  |  　　　　| 　　 　　　　|

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

 row in set (0.01 sec)

mysql> CREATE TABLE tr (c varBINARY());

Query OK,  rows affected (0.04 sec)

mysql> INSERT INTO tr SET c = 'a';

Query OK,  row affected (0.00 sec)

mysql> SELECT HEX(c), c = 'a', c = 'a\0\0' from tr;

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

| HEX(c) | c = 'a' | c = 'a\0\0' |

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

|  　　 |  　　　　| 　　 　　　　|

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

 row in set (0.01 sec)