【MYSQL】查询不区分大小写

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)

注：WINDOWS系统不用修改，系统默认就是1

LINUX 系统默认是0。因为LINUX下的脚本都是区分大小写的。