MySQL中用户的创建及删除

MySQL中创建及删除用户

1. 创建用户:
   命令: CREATE USER 'username'@'host' IDENTIFIED BY 'password';
   说明: username - 即将创建的用户名,
        host - 指定该用户在哪个主机上可以登陆,如果是本地用户可用localhost, 如果想让该用
        户可以从任意远程主机登陆,可以使用通配符%.
        password - 该用户的登陆密码,密码可以为空,如果为空则该用户可以不需要密码登陆服务器.
        例子: CREATE USER 'username'@'localhost' IDENTIFIED BY '123456';
             CREATE USER 'username'@'192.168.1.101_' IDENDIFIED BY '123456';
         CREATE USER 'username'@'%' IDENTIFIED BY '123456';
             CREATE USER 'username'@'%' IDENTIFIED BY '';
             CREATE USER 'username'@'%';
   查看已有用户：
   select user,host,password from mysql.user;
2. 授权:
   命令: GRANT privileges ON databasename.tablename TO 'username'@'host'
   说明: privileges - 用户的操作权限,如SELECT , INSERT , UPDATE 等(详细列表见该文最后面).
        如果要授予所有的权限则使用ALL.;
        databasename - 数据库名,
        tablename-表名,如果要授予该用户对所有数据库和表的相应操作权限则可用*表示, 如*.*.
        例子: GRANT SELECT, INSERT ON test.user TO 'username'@'%';
        GRANT ALL ON *.* TO 'username'@'%';
        注意:用以上命令授权的用户不能给其它用户授权,如果想让该用户可以授权,用以下命令:
        GRANT privileges ON databasename.tablename TO 'username'@'host' WITH GRANT OPTION;
3. 设置与更改用户密码
   命令: SET PASSWORD FOR 'username'@'host' = PASSWORD('newpassword');
        如果是当前登陆用户用SET PASSWORD = PASSWORD("newpassword");
   例子: SET PASSWORD FOR 'username'@'%' = PASSWORD("123456");
   update mysql.user set password=password('新密码') where User="hive" and Host="localhost";
4. 撤销用户权限
   命令: REVOKE privilege ON databasename.tablename FROM 'username'@'host';
   说明: privilege, databasename, tablename - 同授权部分.
   例子: REVOKE SELECT ON *.* FROM 'username'@'%';
   注意: 假如你在给用户'username'@'%'授权的时候是这样的(或类似的):
        GRANT SELECT ON test.user TO 'username'@'%',
        则在使用REVOKE SELECT ON *.* FROM 'username'@'%';
        命令并不能撤销该用户对test数据库中user表的SELECT 操作.
        相反,如果授权使用的是GRANT SELECT ON *.* TO 'username'@'%';
        则REVOKE SELECT ON test.user FROM 'username'@'%';
        命令也不能撤销该用户对test数据库中user表的Select 权限.
   具体信息可以用命令SHOW GRANTS FOR 'username'@'%'; 查看, 或者：
   select User, Host from mysql.user;
   刷新系统权限表：flush privileges;
5. 删除用户
   命令: DROP USER 'username'@'host';
   Delete FROM user Where User="hive" and Host="localhost";
   drop database metastore_db;
  
   附表:在MySQL中的操作权限
   ALTER                    Allows use of ALTER TABLE.
   ALTER ROUTINE            Alters or drops stored routines.
   CREATE                   Allows use of CREATE TABLE.
   CREATE ROUTINE           Creates stored routines.
   CREATE TEMPORARY TABLE   Allows use of CREATE TEMPORARY TABLE.
   CREATE USER              Allows use of CREATE USER, DROP USER,
                            RENAME USER, and REVOKE ALL PRIVILEGES.
   CREATE VIEW              Allows use of CREATE VIEW.
   DELETE                   Allows use of DELETE.
   DROP                     Allows use of DROP TABLE.
   EXECUTE                  Allows the user to run stored routines.
   FILE                     Allows use of SELECT... INTO OUTFILE and
                            LOAD DATA INFILE.
   INDEX                    Allows use of CREATE INDEX and DROP INDEX.
   INSERT                   Allows use of INSERT.
   LOCK TABLES              Allows use of LOCK TABLES on tables for
                            which the user also has SELECT privileges.
   PROCESS                  Allows use of SHOW FULL PROCESSLIST.
   RELOAD                   Allows use of FLUSH.
   REPLICATION              Allows the user to ask where slave or master
   CLIENT                   servers are.
   REPLICATION SLAVE        Needed for replication slaves.
   SELECT                   Allows use of SELECT.
   SHOW DATABASES           Allows use of SHOW DATABASES.
   SHOW VIEW                Allows use of SHOW CREATE VIEW.
   SHUTDOWN                 Allows use of mysqladmin shutdown.
   SUPER                    Allows use of CHANGE MASTER, KILL, PURGE MASTER
                            LOGS, and SET GLOBAL SQL statements. Allows
                            mysqladmin debug command. Allows one extra
                            connection to be made if maximum connections are
                            reached.
   UPDATE                   Allows use of UPDATE.
   USAGE                    Allows connection without any specific privileges.
6. 其他常见操作
   (1)列出所有数据库: show database;
   (2)切换数据库: use '数据库名';
   (3)列出所有表: show tables;
   (4)显示数据表结构: describe 表名;
   (5)删除数据库和数据表: drop database 数据库名;
   //注意，如果数据库名包含“.”，那么在删除时需要加上引用引号，如:
   dropo database `php.sql`;
   drop table 数据表名;