mysql初始化相关

查询mysql版本

mysql -V 或 在mysql中使用：status;

创建数据库

Create DATABASE weibo default charset utf8 COLLATE utf8_general_ci;

显示默认编码设置

show variables like ‘%char%’;

修改默认编码:

SET character_set_client=’utf8′;

SET character_set_connection=’utf8′;

SET character_set_database=’utf8′;

SET character_set_results=’utf8′;

SET character_set_server=’utf8′;

SET character_set_system=’utf8′;

或直接修改 /etc/my.conf

[mysql]

default_character_set=utf8

[mysqld]

default_character_set=utf8

[client]

default_character_set=utf8

需要重启mysql,重启后 show variables like ‘%char%’; 查看默认编码是否已修正

不区分大小写

/etc/my.cnf 中的[mysqld]后添加添加lower_case_table_names=1

创建新用户并赋予相应数据库的操作权限:

insert into mysql.user(Host,User,Password) values(“localhost”,”test”,password(“test”));

flush privileges;

grant all privileges on test.* to chenhaitao@localhost identified by ‘test’;

修改用户密码:

UPDATE user SET password=PASSWORD(“test”) WHERE user=’test’;

flush privileges;

开启远程

mysql -u root –p

mysql>use mysql;

mysql>update user set host = ‘%’ where user = ‘root’;

mysql>select host, user from user;

授权

授权root用户远程访问数据库，并设置密码为123456

GRANT ALL PRIVILEGES ON . TO ‘root’@’%’ IDENTIFIED BY ’123456′ WITH GRANT OPTION;

授权ip地址为172.10.10.10的机器，可以以jk用户的身份访问数据库,并设置密码为123456

GRANT ALL PRIVILEGES ON . TO ‘jk’@’172.10.10.10’ IDENTIFIED BY ’123456′ WITH GRANT OPTION;

授权root用户远程访问数据库，

GRANT ALL PRIVILEGES ON . TO ‘root’@’%’ WITH GRANT OPTION

授权生效

FLUSH PRIVILEGES

jdbc连接时,可以这个设置

xml:

?useUnicode=true&characterEncoding=UTF-8

root 密码丢失

mysql的my.cnf中设置

skip-grant-tables

无密码登录后,重置密码

group_concat

查询:

show variables like ‘%group_concat%’;

配置:

方法一：修改配置文件中参数，新增 group_concat_max_len = 10240

方法二：在会话中实现，全局或当前session中

SET GLOBAL group_concat_max_len=10240;

SET SESSION group_concat_max_len=10240;

max_allowed_packet

查询

show variables like ‘%max_allowed_packet%’;

方法一

在my.conf中设置 max_allowed_packet=16M

方法二

set global max_allowed_packet=20480;