MySQL数据表中内容大小写区分的设置_MySQL

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MySQL数据表中内容大小写区分的设置

 

MYSQL在默认的情况下查询是不区分大小写的，例如： 

 

mysql> create table t1( -> name varchar(10)); Query OK, 0 rows affected (0.09 sec) mysql> insert into t1 values('you'),('You'),('YOU'); Query OK, 3 rows affected (0.05 sec) Records: 3 Duplicates: 0 Warnings: 0 

对这个表，缺省情况下，下面两个查询的结果是一样的：

mysql> select * from t1 where name = 'you'; +------+ | name | +------+ | you | | You | | YOU | +------+ 3 rows in set (0.00 sec) mysql> select * from t1 where name = 'YOU'; +------+ | name | +------+ | you | | You | | YOU | +------+ 3 rows in set (0.00 sec) 

如果想让MYSQL知道你输入的字母是大写还是小写的，修改表：

mysql> alter table t1 change name name varchar(10) binary; Query OK, 3 rows affected (0.20 sec) Records: 3 Duplicates: 0 Warnings: 0 mysql> select * from t1 where name = 'you'; +------+ | name | +------+ | you | +------+ 1 row in set (0.00 sec) mysql> select * from t1 where name = 'YOU'; +------+ | name | +------+ | YOU | +------+ 1 row in set (0.00 sec) 

如果你只是想在SQL语句中实现的话：

mysql> select * from t1 where name = binary 'YOU'; +------+ | name | +------+ | YOU | +------+ 1 row in set (0.02 sec) mysql> select * from t1 where name = binary 'you'; +------+ | name | +------+ | you | +------+ 1 row in set (0.00 sec) 

如果不想这么麻烦而想服务一开启就让大小写一致的话：

可以修改my.ini或者my.cnf

[mysqld] lower_case_table_names=1 （0：区分；1：不区分） 

然后重启MYSQL服务。

mysql> show variables like '%case_table%'; +------------------------+-------+ | Variable_name | Value | +------------------------+-------+ | lower_case_table_names | 1 | +------------------------+-------+ 1 row in set (0.00 sec)

 

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