• log into the mysql

for localhost
mysql -u username -ppasswd(there is no space)
for ip
mysql -h ip -P port -u username -ppasswd(there is no space,-P default 3306)

• show operators

mysql> show databases;
+--------------------+
| Database           |
+--------------------+
| information_schema |
| db_followtrade     |
| db_user_msg        |
| mysql              |
| performance_schema |
| user               |
+--------------------+
6 rows in set (0.00 sec)

use user;

mysql> show tables;
+----------------+
| Tables_in_user |
+----------------+
| t_user         |
+----------------+
1 row in set (0.00 sec)

• others show operator

mysql> show processlist;
+----+------+-----------+------+---------+------+-------+------------------+
| Id | User | Host      | db   | Command | Time | State | Info             |
+----+------+-----------+------+---------+------+-------+------------------+
| 42 | root | localhost | user | Query   |    0 | init  | show processlist |
+----+------+-----------+------+---------+------+-------+------------------+
1 row in set (0.00 sec)

mysql> show global variables like "%datadir%";
+---------------+-----------------+
| Variable_name | Value           |
+---------------+-----------------+
| datadir       | /var/lib/mysql/ |
+---------------+-----------------+
1 row in set (0.00 sec)

mysql> show global variables like "%cache%";
+--------------------------------+----------------------+
| Variable_name                  | Value                |
+--------------------------------+----------------------+
| binlog_cache_size              | 32768                |
| binlog_stmt_cache_size         | 32768                |
| have_query_cache               | YES                  |
| host_cache_size                | 279                  |
| innodb_disable_sort_file_cache | OFF                  |
| innodb_ft_cache_size           | 8000000              |
| innodb_ft_result_cache_limit   | 2000000000           |
| innodb_ft_total_cache_size     | 640000000            |
| key_cache_age_threshold        | 300                  |
| key_cache_block_size           | 1024                 |
| key_cache_division_limit       | 100                  |
| max_binlog_cache_size          | 18446744073709547520 |
| max_binlog_stmt_cache_size     | 18446744073709547520 |
| metadata_locks_cache_size      | 1024                 |
| query_cache_limit              | 1048576              |
| query_cache_min_res_unit       | 4096                 |
| query_cache_size               | 16777216             |
| query_cache_type               | OFF                  |
| query_cache_wlock_invalidate   | OFF                  |
| stored_program_cache           | 256                  |
| table_definition_cache         | 1400                 |
| table_open_cache               | 2000                 |
| table_open_cache_instances     | 1                    |
| thread_cache_size              | 8                    |
+--------------------------------+----------------------+
24 rows in set (0.01 sec)

show character set;
show collation;

mysql> show create database db_user_msg ;
+-------------+------------------------------------------------------------------------+
| Database    | Create Database                                                        |
+-------------+------------------------------------------------------------------------+
| db_user_msg | CREATE DATABASE `db_user_msg` /*!40100 DEFAULT CHARACTER SET latin1 */ |
+-------------+------------------------------------------------------------------------+
1 row in set (0.00 sec)

mysql> show tables;
+-----------------------+
| Tables_in_db_user_msg |
+-----------------------+
| t_manage_user         |
| t_send_log            |
| t_user                |
+-----------------------+
3 rows in set (0.00 sec)

mysql> show create table t_manage_user\G
*************************** 1. row ***************************
       Table: t_manage_user
Create Table: CREATE TABLE `t_manage_user` (
  `name` varchar(20) DEFAULT NULL,
  `wx_id` varchar(20) DEFAULT NULL,
  `phone` varchar(20) DEFAULT NULL,
  `email` varchar(20) DEFAULT NULL,
  `status` tinyint(1) DEFAULT NULL,
  `role` varchar(20) DEFAULT NULL
) ENGINE=MyISAM DEFAULT CHARSET=utf8
1 row in set (0.01 sec)

mysql> show engines;
+--------------------+---------+----------------------------------------------------------------+--------------+------+------------+
| Engine             | Support | Comment                                                        | Transactions | XA   | Savepoints |
+--------------------+---------+----------------------------------------------------------------+--------------+------+------------+
| MEMORY             | YES     | Hash based, stored in memory, useful for temporary tables      | NO           | NO   | NO         |
| CSV                | YES     | CSV storage engine                                             | NO           | NO   | NO         |
| MRG_MYISAM         | YES     | Collection of identical MyISAM tables                          | NO           | NO   | NO         |
| BLACKHOLE          | YES     | /dev/null storage engine (anything you write to it disappears) | NO           | NO   | NO         |
| MyISAM             | YES     | MyISAM storage engine                                          | NO           | NO   | NO         |
| PERFORMANCE_SCHEMA | YES     | Performance Schema                                             | NO           | NO   | NO         |
| ARCHIVE            | YES     | Archive storage engine                                         | NO           | NO   | NO         |
| InnoDB             | DEFAULT | Supports transactions, row-level locking, and foreign keys     | YES          | YES  | YES        |
| FEDERATED          | NO      | Federated MySQL storage engine                                 | NULL         | NULL | NULL       |
+--------------------+---------+----------------------------------------------------------------+--------------+------+------------+

mysql> show grants;
mysql> show grants for current_user;
+----------------------------------------------------------------------------------------------------------------------------------------+
| Grants for root@localhost                                                                                                              |
+----------------------------------------------------------------------------------------------------------------------------------------+
| GRANT ALL PRIVILEGES ON *.* TO ‘root‘@‘localhost‘ IDENTIFIED BY PASSWORD ‘*81F5E21E35407D884A6CD4A731AEBFB6AF209E1B‘ WITH GRANT OPTION |
| GRANT PROXY ON ‘‘@‘‘ TO ‘root‘@‘localhost‘ WITH GRANT OPTION                                                                           |
+----------------------------------------------------------------------------------------------------------------------------------------+

show index from one_table_name;

mysql> show privileges;
+-------------------------+---------------------------------------+-------------------------------------------------------+
| Privilege               | Context                               | Comment                                               |
+-------------------------+---------------------------------------+-------------------------------------------------------+
| Alter                   | Tables                                | To alter the table                                    |
| Alter routine           | Functions,Procedures                  | To alter or drop stored functions/procedures          |
| Create                  | Databases,Tables,Indexes              | To create new databases and tables                    |
| Create routine          | Databases                             | To use CREATE FUNCTION/PROCEDURE                      |
| Create temporary tables | Databases                             | To use CREATE TEMPORARY TABLE                         |
| Create view             | Tables                                | To create new views                                   |
| Create user             | Server Admin                          | To create new users                                   |
| Delete                  | Tables                                | To delete existing rows                               |
| Drop                    | Databases,Tables                      | To drop databases, tables, and views                  |
| Event                   | Server Admin                          | To create, alter, drop and execute events             |
| Execute                 | Functions,Procedures                  | To execute stored routines                            |
| File                    | File access on server                 | To read and write files on the server                 |
| Grant option            | Databases,Tables,Functions,Procedures | To give to other users those privileges you possess   |
| Index                   | Tables                                | To create or drop indexes                             |
| Insert                  | Tables                                | To insert data into tables                            |
| Lock tables             | Databases                             | To use LOCK TABLES (together with SELECT privilege)   |
| Process                 | Server Admin                          | To view the plain text of currently executing queries |
| Proxy                   | Server Admin                          | To make proxy user possible                           |
| References              | Databases,Tables                      | To have references on tables                          |
| Reload                  | Server Admin                          | To reload or refresh tables, logs and privileges      |
| Replication client      | Server Admin                          | To ask where the slave or master servers are          |
| Replication slave       | Server Admin                          | To read binary log events from the master             |
| Select                  | Tables                                | To retrieve rows from table                           |
| Show databases          | Server Admin                          | To see all databases with SHOW DATABASES              |
| Show view               | Tables                                | To see views with SHOW CREATE VIEW                    |
| Shutdown                | Server Admin                          | To shut down the server                               |
| Super                   | Server Admin                          | To use KILL thread, SET GLOBAL, CHANGE MASTER, etc.   |
| Trigger                 | Tables                                | To use triggers                                       |
| Create tablespace       | Server Admin                          | To create/alter/drop tablespaces                      |
| Update                  | Tables                                | To update existing rows                               |
| Usage                   | Server Admin                          | No privileges - allow connect only                    |
+-------------------------+---------------------------------------+-------------------------------------------------------+

show status;
show triggers;