新建一个用户admin1对所有的库表完全权限，允许从任何地方访问，密码设为123456
Query OK, 0 rows affected, 1 warning (0.00 sec)
语法为

grant 权限列表 on 库名.表名 用户名@“用户地址” identified by " 密码" [ with grant opion ];

mysql> grant all on . to admin2@"%" identified by "123456" with grant option;
Query OK, 0 rows affected, 1 warning (0.00 sec)
all 匹配所有权限
. 匹配所有库和表
” %“ 匹配所有主机

授权用户admin3 允许对192.168.4.0/24网段访问

mysql> grant all on . to admin3@'192.168.4.0/24' identified by "123456" with grant option;
Query OK, 0 rows affected, 1 warning (0.00 sec)

对用户admin4在daydb4.user1仅有查询权限 登录密码为123456
mysql> grant select on daydb4.user1 to admin4@"localhost" identified by "123456" with grant option;
Query OK, 0 rows affected, 1 warning (0.00 sec)

授权admin5 允许本机访问，对daydb4任何表有查询 更改 插入 删除 权限 密码123456

mysql> grant select,update,delete,insert on daydb4.* to admin4@"localhost" identified by "123456" with grant option;
Query OK, 0 rows affected, 1 warning (0.01 sec)

用户查看自己的授权

mysql> show grants;

+---------------------------------------------------------------------+
| Grants for root@localhost |
+---------------------------------------------------------------------+
| GRANT ALL PRIVILEGES ON . TO 'root'@'localhost' WITH GRANT OPTION |
| GRANT PROXY ON ''@'' TO 'root'@'localhost' WITH GRANT OPTION |
+---------------------------------------------------------------------+
2 rows in set (0.00 sec)

root 查看其他人用户的授权
show grant for 用户名@“客户端地址”;

mysql> show grants for admin4@"localhost" \g;
+----------------------------------------------------------------------------------------------+
| Grants for admin4@localhost |
+----------------------------------------------------------------------------------------------+
| GRANT USAGE ON . TO 'admin4'@'localhost' |
| GRANT SELECT, INSERT, UPDATE, DELETE ON daydb4.* TO 'admin4'@'localhost' WITH GRANT OPTION |
| GRANT SELECT ON daydb4.user1 TO 'admin4'@'localhost' WITH GRANT OPTION |
+----------------------------------------------------------------------------------------------+
3 rows in set (0.00 sec)
用户链接后修改密码
set password=password("新密码");

[root@MySQL50 ~]# mysql -uadmin4 -p654321
[root@MySQL50 ~]# mysql -uadmin4 -p654321
mysql: [Warning] Using a password on the command line interface can be insecure.
Welcome to the MySQL monitor. Commands end with ; or \g.
Your MySQL connection id is 41
Server version: 5.7.17 MySQL Community Server (GPL)

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Oracle is a registered trademark of Oracle Corporation and/or its
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owners.

Type 'help;' or '\h' for help. Type '\c' to clear the current input statement.

mysql>
mysql> set password=password("123456");
Query OK, 0 rows affected, 1 warning (0.00 sec)