--------------+
| 'AbC' regexp binary '^a' |
+--------------------------+
| 0 |
+--------------------------+
1 row in set
mysql> select 'AbC' regexp binary '^A';
+--------------------------+
| 'AbC' regexp binary '^A' |
+--------------------------+
| 1 |
+--------------------------+
在选择表或者是通过数据库函数如user(),database()等获取数据的测试情况:
- 在查询表中字段数据时,无论是否进行编码 ,大小写都是不强匹配
mysql> select * from test where user like 'A%';
+---------+-------+---------------------------------------+
| user_id | user | password |
+---------+-------+---------------------------------------+
| 1 | admin | 5f4dcc3b5aa765d61d8327deb882cf99|
| 2 | ADMIN| 5f4dcc3b5aa765d61d8327deb882cf99|
+---------+-------+---------------------------------------+
2 rows in set
mysql> select * from test where user like char(65,37) ;
+---------+-------+---------------------------------------+
| user_id | user | password |
+---------+-------+---------------------------------------+
| 1 | admin | 5f4dcc3b5aa765d61d8327deb882cf99|
| 2 | ADMIN| 5f4dcc3b5aa765d61d8327deb882cf99|
+---------+-------+---------------------------------------+
2 rows in set
mysql> select * from test where user regexp '^A';
+---------+-------+---------------------------------------+
| user_id | user | password |
+---------+-------+---------------------------------------+
| 1 | admin | 5f4dcc3b5aa765d61d8327deb882cf99|
| 2 | ADMIN| 5f4dcc3b5aa765d61d8327deb882cf99|
+---------+-------+---------------------------------------+
2 rows in set
mysql> select * from test where user regexp 0x5E61;
+---------+-------+---------------------------------------+
| user_id | user | password |
+---------+-------+---------------------------------------+
| 1 | admin | 5f4dcc3b5aa765d61d8327deb882cf99|
| 2 | ADMIN| 5f4dcc3b5aa765d61d8327deb882cf99|
+---------+-------+---------------------------------------+
2 rows in set
mysql> select * from test where user regexp binary 0x5E41;
+---------+-------+----------------------------------------------+
| user_id | user | password |
+---------+-------+----------------------------------------------+
| 2 | ADMIN | 5f4dcc3b5aa765d61d8327deb882cf99 |
+---------+-------+----------------------------------------------+
1 row in set
0x02 测试结论
MYSQL大小写不进行强匹配的。要想匹配大小写可以使用binary,或者使用http://www.cnblogs.com/Z3roTo0ne/p/6883132.html中的两次16进制编码的方式。进行大小写强匹配。
0x03 另外的一种方式
使用10进制和16进制混合也可以达到区分大小写的效果,因为大小写的16进制是不一样的。
mysql> select conv(hex(substr((user()),1,8)),16,10);
+---------------------------------------+
| conv(hex(substr((user()),1,8)),16,10) |
+---------------------------------------+
| 8245931987826405219 |
+---------------------------------------+
1 row in set
mysql> select unhex(conv((8245931987826405219),10,16));
+----------------------------------------------------+
| unhex(conv((8245931987826405219),10,16)) |
+----------------------------------------------------+
| root@loc |
+----------------------------------------------------+
1 row in set