http://dev.mysql.com/doc/refman/5.0/en/case-sensitivity.html

The default character set and collation are latin1 and latin1_swedish_ci, so nonbinary string comparisons are case insensitive by default. This means that if you search with col_name LIKE 'a%', you get all column values that start with A or a. To make this search case sensitive, make sure that one of the operands has a case sensitive or binary collation. For example, if you are comparing a column and a string that both have the latin1 character set, you can use the COLLATE operator to cause either operand to have the latin1_general_cs or latin1_bin collation:

col_name COLLATE latin1_general_cs LIKE 'a%'
col_name LIKE 'a%' COLLATE latin1_general_cs
col_name COLLATE latin1_bin LIKE 'a%'
col_name LIKE 'a%' COLLATE latin1_bin

如果希望始终以区分大小写的方式对待列，请使用区分大小写或二进制排序规则来声明它。

不需要改变任何DB级别，只是你必须改变SQL查询它将工作。

的例子,

“SELECT * FROM <TABLE> where userId = ' ' ' + iv_userId + ' ' AND password = ' ' ' ' ' + iv_password + ' '";

二进制关键字将区分大小写。

要在使用BINARY之前使用索引，如果有大型表，可以这样做。

SELECT
   *
FROM
   (SELECT * FROM `table` WHERE `column` = 'value') as firstresult
WHERE
   BINARY `column` = 'value'

子查询将生成一个非常小的不区分大小写的子集，然后选择其中唯一区分大小写的匹配项。

好消息是，如果你需要进行区分大小写的查询，这很容易做到:

SELECT *  FROM `table` WHERE BINARY `column` = 'value'

http://dev.mysql.com/doc/refman/5.0/en/case-sensitivity.html

The default character set and collation are latin1 and latin1_swedish_ci, so nonbinary string comparisons are case insensitive by default. This means that if you search with col_name LIKE 'a%', you get all column values that start with A or a. To make this search case sensitive, make sure that one of the operands has a case sensitive or binary collation. For example, if you are comparing a column and a string that both have the latin1 character set, you can use the COLLATE operator to cause either operand to have the latin1_general_cs or latin1_bin collation:

col_name COLLATE latin1_general_cs LIKE 'a%'
col_name LIKE 'a%' COLLATE latin1_general_cs
col_name COLLATE latin1_bin LIKE 'a%'
col_name LIKE 'a%' COLLATE latin1_bin

如果希望始终以区分大小写的方式对待列，请使用区分大小写或二进制排序规则来声明它。

Mysql默认情况下不区分大小写，请尝试将语言排序规则更改为latin1_general_cs