设置排序规则：
区分大小写的查询：
mysql> select * from user; +----+----------+-----------+------+------+ | id | username | loginname | pwd | sex | +----+----------+-----------+------+------+ | 1 | 小明 | xiaoming | 123 | 1 | | 2 | 管理员 | Admin | 123 | 1 | +----+----------+-----------+------+------+ 2 rows in set (0.00 sec) mysql> select * from user where loginname="Admin"; +----+----------+-----------+------+------+ | id | username | loginname | pwd | sex | +----+----------+-----------+------+------+ | 2 | 管理员 | Admin | 123 | 1 | +----+----------+-----------+------+------+ 1 row in set (0.00 sec) mysql> select * from user where loginname="admin"; Empty set (0.00 sec)