MySQL_01 常用命令

1. 查看版本
MariaDB [web1]> SELECT VERSION();

2. 查看所有数据库
MariaDB [web1]> SHOW DATABASES;

3. 进入 web1 库
MariaDB [(none)]> USE web1;

4. 库中查看表
MariaDB [web1]> SHOW TABLES;

5. 查看其他库中表
MariaDB [web1]> SHOW TABLES FROM web2;

6. 查看创建表语句
MariaDB [web1]> SHOW CREATE TABLE score;

7. 查看表结构
MariaDB [web1]> DESC score;

8. 查看当前所在库
MariaDB [web1]> SELECT DATABASE();

9. 查看数据库支持的存储引擎
MariaDB [web1]> SHOW ENGINES;
+--------------------+---------+----------------------------------------------------------------------------------+--------------+------+------------+
| Engine             | Support | Comment                                                                          | Transactions | XA   | Savepoints |
+--------------------+---------+----------------------------------------------------------------------------------+--------------+------+------------+
| MEMORY             | YES     | Hash based, stored in memory, useful for temporary tables                        | NO           | NO   | NO         |
| MRG_MyISAM         | YES     | Collection of identical MyISAM tables                                            | NO           | NO   | NO         |
| CSV                | YES     | Stores tables as CSV files                                                       | NO           | NO   | NO         |
| BLACKHOLE          | YES     | /dev/null storage engine (anything you write to it disappears)                   | NO           | NO   | NO         |
| MyISAM             | YES     | Non-transactional engine with good performance and small data footprint          | NO           | NO   | NO         |
| ARCHIVE            | YES     | gzip-compresses tables for a low storage footprint                               | NO           | NO   | NO         |
| FEDERATED          | YES     | Allows to access tables on other MariaDB servers, supports transactions and more | YES          | NO   | YES        |
| PERFORMANCE_SCHEMA | YES     | Performance Schema                                                               | NO           | NO   | NO         |
| SEQUENCE           | YES     | Generated tables filled with sequential values                                   | YES          | NO   | YES        |
| InnoDB             | DEFAULT | Supports transactions, row-level locking, foreign keys and encryption for tables | YES          | YES  | YES        |
| Aria               | YES     | Crash-safe tables with MyISAM heritage                                           | NO           | NO   | NO         |
+--------------------+---------+----------------------------------------------------------------------------------+--------------+------+------------+

10. 查看系统变量及其值
MariaDB [web1]> SHOW VARIABLES;

11. 查看某个系统变量
MariaDB [web1]> SHOW VARIABLES LIKE '%wait_timeout%';
+--------------------------+-------+
| Variable_name            | Value |
+--------------------------+-------+
| innodb_lock_wait_timeout | 50    |
| lock_wait_timeout        | 86400 |
| wait_timeout             | 28800 |
+--------------------------+-------+

12. 语言分类

DQL (Data Query Language)            数据查询语言           select等

DML (Data Manipulate Language)       数据操作语言           insert、update、delete等

DDL (Data Define Language)           数据定义语言           create、drop、alter语句

TCL (Transaction Control Language)   事务控制语言           commit,rollback等