使用命令行查看数据库的默认字符集：
show variables like "%character%";
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show variables like "%collation%";
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注释：此时数据库的默认字符集为 utf8_general_ci
使用命令行查看数据库的最大连接数：
show variables like '%max_connections%';
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使用命令行查看数据库的“最大可打开文件数”：
show global variables like '%open_files_limit%';
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查看所有数据库用户及其主机信息：
select user,host from mysql.user;
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查看数据库管理员root@localhost的权限：（可以管理所有的库）
MariaDB [(none)]> show grants for root@localhost;
+-------------------------------------------------------------------------------
---------------------------------------------------------+
| Grants for root@localhost
|
+-------------------------------------------------------------------------------
---------------------------------------------------------+
| GRANT ALL PRIVILEGES ON *.* TO 'root'@'localhost' IDENTIFIED BY PASSWORD '*41DDB5DFD213B288EE050BD64DC6AA36815A3486' WITH GRANT OPTION |
| GRANT PROXY ON ''@'%' TO 'root'@'localhost' WITH GRANT OPTION
|
+-------------------------------------------------------------------------------
---------------------------------------------------------+
2 rows in set (0.00 sec)
查看所有的库：
MariaDB [(none)]> show databases;
+--------------------+
| Database |
+--------------------+
| discuz |
| information_schema |
| mysql |
| performance_schema |
| test |
| wordpress |
+--------------------+
6 rows in set (0.00 sec)
