MySQL資料庫認證密碼有兩種方式:
1：MySQL 4.1版本之前是MySQL323加密
2：MySQL 4.1和之後的版本都是MySQLSHA1加密

還有函式:AES_ENCRYPT()加密函式和AES_DECRYPT()解密函式和MD5()加密。

MySQL資料庫中自帶old_password(str)和password(str)函式,前者是MySQL323加密,後者是MySQLSHA1方式加密;
MYSQL323加密中生成的是16位字串,而在MySQLSHA1中生存的是41位字串,其中*是不加入實際的密碼運算中,就是說MySQLSHA1加密的密碼的實際位數是40位;

MYSQL323對應於old_password(str)函式
MYSQLSHA1對應於password(str)函式

注：AES_ENCRYPT()加密函式和AES_DECRYPT()解密函式都需要一個“key”來協助加密。
eg:select aes_encrypt('kaka123','key');
   select aes_decrypt(aes_encrypt('kaka123','key'),'key');
 

mysql> select old_password('kaka123');
+-------------------------+
| old_password('kaka123') |
+-------------------------+
| 2ee53a20184c9267        |
+-------------------------+
1 row in set, 1 warning (0.00 sec)

2.MYSQLSHA1對應於password(str)函式加密：

 mysql> select password('kaka123');
+-------------------------------------------+
| password('kaka123')                       |
+-------------------------------------------+
| *90B3D884FB6092549F244125549B77C000A0F9C6 |
+-------------------------------------------+
1 row in set (0.00 sec)
 

3.MYSQL MD5()加密：

mysql> select md5('kaka123');
+----------------------------------+
| md5('kaka123')                   |
+----------------------------------+
| 5d052f1e32af4e4ac2544a5fc2a9b992 |
+----------------------------------+
1 row in set (0.00 sec)

4.AES_ENCRYPT()加密函式

mysql> select aes_encrypt('kaka123','key');
+------------------------------+
| aes_encrypt('kaka123','key') |
+------------------------------+
| D#jA
                 |
+------------------------------+
1 row in set (0.00 sec)
 

5.AES_DECRYPT()解密函式

mysql> select aes_decrypt(aes_encrypt('kaka123','key'),'key');
+-------------------------------------------------+
| aes_decrypt(aes_encrypt('kaka123','key'),'key') |
+-------------------------------------------------+
| kaka123                                         |
+-------------------------------------------------+
1 row in set (0.00 sec)

4.AES_ENCRYPT()加密函式

mysql> select host,user,password from mysql.user;
+----------------+------+-------------------------------------------+
| host           | user | password                                  |
+----------------+------+-------------------------------------------+
| localhost      | root | *71ABCA8B06D46066CEF8062A75256E66243D0FC8 |
| tony\_ts\_tian | root | *71ABCA8B06D46066CEF8062A75256E66243D0FC8 |
| 127.0.0.1      | root | *71ABCA8B06D46066CEF8062A75256E66243D0FC8 |
| ::1            | root | *71ABCA8B06D46066CEF8062A75256E66243D0FC8 |
| %              | root | *71ABCA8B06D46066CEF8062A75256E66243D0FC8 |
| %              | kaka | *6BB4837EB74329105EE4568DDA7DC67ED2CA2AD9 |
+----------------+------+-------------------------------------------+
6 rows in set (0.00 sec)

mysql> update mysql.user set password=AES_ENCRYPT("kaka123",'key') where host='%' and user='kaka';
Query OK, 1 row affected (0.00 sec)
Rows matched: 1  Changed: 1  Warnings: 0

mysql>  select host,user,password from mysql.user;
+----------------+------+-------------------------------------------+
| host           | user | password                                  |
+----------------+------+-------------------------------------------+
| localhost      | root | *71ABCA8B06D46066CEF8062A75256E66243D0FC8 |
| tony\_ts\_tian | root | *71ABCA8B06D46066CEF8062A75256E66243D0FC8 |
| 127.0.0.1      | root | *71ABCA8B06D46066CEF8062A75256E66243D0FC8 |
| ::1            | root | *71ABCA8B06D46066CEF8062A75256E66243D0FC8 |
| %              | root | *71ABCA8B06D46066CEF8062A75256E66243D0FC8 |
| %              | kaka | œDŸ#jAÂ
                          |       ¯Ll 
+----------------+------+-------------------------------------------+
6 rows in set (0.00 sec)

5.AES_DECRYPT()解密函式

mysql> select host,user,AES_DECRYPT(password,'key') from mysql.user;
+----------------+------+-----------------------------+
| host           | user | AES_DECRYPT(password,'key') |
+----------------+------+-----------------------------+
| localhost      | root | NULL                        |
| tony\_ts\_tian | root | NULL                        |
| 127.0.0.1      | root | NULL                        |
| ::1            | root | NULL                        |
| %              | root | NULL                        |
| %              | kaka | kaka123                     |
+----------------+------+-----------------------------+
6 rows in set (0.00 sec)

mysql不區分大小寫:

修改MySql Server安裝目錄下的 my.ini 或my.conf檔案

在mysqld節下加入下面一行
lower_case_table_names=0 
（0：大小寫敏感；1：大小寫不敏感）最後重啟一下MySql服務即可。 
修改對於新建的表，老表無效

#解決mysql欄位不區分大小寫:

CREATE TABLE `user`(
	`id` BIGINT NOT NULL AUTO_INCREMENT COMMENT'使用者登入表主鍵id',
	`uname` VARCHAR(35) NOT NULL COMMENT'使用者登入名',
	`upass` VARCHAR(32) NOT NULL COMMENT'使用者登入密碼',
	`ustatus` VARCHAR(2) NOT NULL DEFAULT '0' COMMENT'使用者登入狀態,0為正常，1為鎖定',
	UNIQUE (`uname`),
	PRIMARY KEY(`id`)
)ENGINE = INNODB COLLATE=utf8_bin COMMENT='使用者登入表';

注：COLLATE=utf8_bin