MYSQL在默认的情况下查询是不区分大小写的

转载 http://blog.chinaunix.net/u/29134/showart_355336.html  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1LINUX 系统默认是0。因为LINUX下的脚本都是区分大小写的。