我有一个函数,返回5个混合大小写字符。如果我对这个字符串进行查询,不管大小写,它都会返回值。
如何使MySQL字符串查询区分大小写?
我有一个函数,返回5个混合大小写字符。如果我对这个字符串进行查询,不管大小写,它都会返回值。
如何使MySQL字符串查询区分大小写?
当前回答
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)
其他回答
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
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
太好了!
我和你们分享一个比较密码的函数的代码:
SET pSignal =
(SELECT DECODE(r.usignal,'YOURSTRINGKEY') FROM rsw_uds r WHERE r.uname =
in_usdname AND r.uvige = 1);
SET pSuccess =(SELECT in_usdsignal LIKE BINARY pSignal);
IF pSuccess = 1 THEN
/*Your code if match*/
ELSE
/*Your code if don't match*/
END IF;
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)
下面是MySQL版本等于或高于5.5的情况。
添加到/etc/mysql/my.cnf
[mysqld]
...
character-set-server=utf8
collation-server=utf8_bin
...
我尝试的所有其他排序似乎都不区分大小写,只有“utf8_bin”有效。
在这之后不要忘记重新启动mysql:
sudo service mysql restart
根据http://dev.mysql.com/doc/refman/5.0/en/case-sensitivity.html,还有一个“latin1_bin”。
“utf8_general_cs”不被mysql启动接受。(我把“_cs”读成“区分大小写”- ??)