# 数据库与表显示、创建、删除
## 数据库显示
> **show databases;**
```
mysql> show databases;
+--------------------+
| Database |
+--------------------+
| information_schema |
| app_blogcurder |
| auth_demo |
| canzhieps |
| cmsdemo |
| mysql |
| onethink |
| performance_schema |
| ranzhi |
| thinkems |
| thinksns_3_1 |
| thinksns_4_0 |
+--------------------+
12 rows in set (0.01 sec)
```
## 创建数据库
> **create database 库名字;**
```
mysql> create database test;
Query OK, 1 row affected (0.00 sec)
```
## 删除数据库
> **drop database [IF EXISTS] 库名字;**
```
mysql> drop database test;
Query OK, 0 rows affected (0.01 sec)
```
## 选中数据库
>[success] **use 库名;**
```
mysql> use mysql
Database changed
mysql> \s
--------------
mysql Ver 14.14 Distrib 5.6.17, for Win64 (x86_64)
Connection id: 8
Current database: mysql
Current user: root@localhost
SSL: Not in use
Using delimiter: ;
Server version: 5.6.17 MySQL Community Server (GPL)
```
## 显示表
### 数据表
> **show tables;**[需要县选中数据库]
```
mysql> use mysql
Database changed
mysql> show tables;
+---------------------------+
| Tables_in_mysql |
+---------------------------+
| columns_priv |
| db |
| event |
| func |
| general_log |
... ...
```
### 显示表结构
> **desc 表名; 或者 describe 表名;**
```
mysql> desc db;
+-----------------------+---------------+------+-----+---------+-------+
| Field | Type | Null | Key | Default | Extra |
+-----------------------+---------------+------+-----+---------+-------+
| Host | char(60) | NO | PRI | | |
| Db | char(64) | NO | PRI | | |
| User | char(16) | NO | PRI | | |
... ...
```
## 表创建
```
CREATE TABLE `member` (
`uid` int(10) unsigned NOT NULL AUTO_INCREMENT COMMENT '用户ID',
`nickname` char(16) NOT NULL DEFAULT '' COMMENT '昵称',
`sex` tinyint(3) unsigned NOT NULL DEFAULT '0' COMMENT '性别',
`birthday` date NOT NULL DEFAULT '0000-00-00' COMMENT '生日',
`qq` char(10) NOT NULL DEFAULT '' COMMENT 'qq号',
`score` mediumint(8) NOT NULL DEFAULT '0' COMMENT '用户积分',
`login` int(10) unsigned NOT NULL DEFAULT '0' COMMENT '登录次数',
`reg_ip` bigint(20) NOT NULL DEFAULT '0' COMMENT '注册IP',
`reg_time` int(10) unsigned NOT NULL DEFAULT '0' COMMENT '注册时间',
`last_login_ip` bigint(20) NOT NULL DEFAULT '0' COMMENT '最后登录IP',
`last_login_time` int(10) unsigned NOT NULL DEFAULT '0' COMMENT '最后登录时间',
`status` tinyint(4) NOT NULL DEFAULT '0' COMMENT '会员状态',
PRIMARY KEY (`uid`),
KEY `status` (`status`)
) ENGINE=MyISAM DEFAULT CHARSET=utf8 COMMENT='会员表';
```
## 表删除
> **drop table 表名;**
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