不使用=运算符，您可能希望使用LIKE或LIKE二进制

// this returns 1 (true)
select 'A' like 'a'

// this returns 0 (false)
select 'A' like binary 'a'


select * from user where username like binary 'a'

在它的条件下，它会取a和不取a

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'

对于那些希望使用RLIKE或REGEXP与正则表达式进行区分大小写的比较的人来说，你可以使用REGEXP_LIKE()来匹配匹配类型c，如下所示:

SELECT * FROM `table` WHERE REGEXP_LIKE(`column`, 'value', 'c');

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。

克雷格·怀特(Craig White)发布的答案有很大的性能损失

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

因为它不使用索引。所以，要么你需要像这里提到的那样改变表的排序规则https://dev.mysql.com/doc/refman/5.7/en/case-sensitivity.html。

OR

最简单的解决方法，你应该使用二进制值。

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

E.g.

mysql> EXPLAIN SELECT * FROM temp1 WHERE BINARY col1 = "ABC" AND col2 = "DEF" ;
+----+-------------+--------+------+---------------+------+---------+------+--------+-------------+
| id | select_type | table  | type | possible_keys | key  | key_len | ref  | rows   | Extra       |
+----+-------------+--------+------+---------------+------+---------+------+--------+-------------+
|  1 | SIMPLE      | temp1  | ALL  | NULL          | NULL | NULL    | NULL | 190543 | Using where |
+----+-------------+--------+------+---------------+------+---------+------+--------+-------------+

VS

mysql> EXPLAIN SELECT * FROM temp1 WHERE col1 = BINARY "ABC" AND col2 = "DEF" ;
+----+-------------+-------+-------+---------------+---------------+---------+------+------+------------------------------------+
| id | select_type | table | type  | possible_keys | key           | key_len | ref  | rows | Extra                              |
+----+-------------+-------+-------+---------------+---------------+---------+------+------+------------------------------------+
|  1 | SIMPLE      | temp1 | range | col1_2e9e898e | col1_2e9e898e | 93      | NULL |    2 | Using index condition; Using where |
+----+-------------+-------+-------+---------------+---------------+---------+------+------+------------------------------------+
enter code here

set中的1行(0.00秒)

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。