MYSQL笔记：使用MYSQL

选择数据库

使用USE关键字打开数据库
例如选择data数据库：

use data

成功后会输出

Database changed

数据库和数据表

显示可用的数据库：

mysql> show databases;
+--------------------+
| Database           |
+--------------------+
| information_schema |
| chat               |
| mysql              |
| performance_schema |
| sys                |
+--------------------+
5 rows in set (0.01 sec)

为了获得一个数据库内的表的列表，使用SHOW TABLES;，如下所示：

Database changed
mysql> show tables;
+-----------------------------------------------+
| Tables_in_sys                                 |
+-----------------------------------------------+
| host_summary                                  |
| host_summary_by_file_io                       |
| host_summary_by_file_io_type                  |
| host_summary_by_stages                        |
| host_summary_by_statement_latency             |
| host_summary_by_statement_type                |
| innodb_buffer_stats_by_schema                 |

显示列：

mysql> show columns from host_summary  ;
+------------------------+---------------+------+-----+---------+-------+
| Field                  | Type          | Null | Key | Default | Extra |
+------------------------+---------------+------+-----+---------+-------+
| host                   | varchar(60)   | YES  |     | NULL    |       |
| statements             | decimal(64,0) | YES  |     | NULL    |       |
| statement_latency      | text          | YES  |     | NULL    |       |
| statement_avg_latency  | text          | YES  |     | NULL    |       |
| table_scans            | decimal(65,0) | YES  |     | NULL    |       |
| file_ios               | decimal(64,0) | YES  |     | NULL    |       |
| file_io_latency        | text          | YES  |     | NULL    |       |
| current_connections    | decimal(41,0) | YES  |     | NULL    |       |
| total_connections      | decimal(41,0) | YES  |     | NULL    |       |
| unique_users           | bigint(21)    | NO   |     | 0       |       |
| current_memory         | text          | YES  |     | NULL    |       |
| total_memory_allocated | text          | YES  |     | NULL    |       |
+------------------------+---------------+------+-----+---------+-------+
12 rows in set (0.00 sec)

显示show语句其它功能：

mysql> help show;
Name: 'SHOW'
Description:
SHOW has many forms that provide information about databases, tables,
columns, or status information about the server. This section describes
those following:SHOW {BINARY | MASTER} LOGS
SHOW BINLOG EVENTS [IN 'log_name'] [FROM pos] [LIMIT [offset,] row_count]
SHOW {CHARACTER SET | CHARSET} [like_or_where]
SHOW COLLATION [like_or_where]
SHOW [FULL] COLUMNS FROM tbl_name [FROM db_name] [like_or_where]
SHOW CREATE DATABASE db_name
SHOW CREATE EVENT event_name
SHOW CREATE FUNCTION func_name
SHOW CREATE PROCEDURE proc_name
...