# 快速起步

## 登陆数据库

```
mysql -u root -p
```

```
Type 'help;' or '\h' for help. Type '\c' to clear the current input statement.

mysql>
```

## 查询库 show databases

```
mysql> show databases;
+--------------------+
| Database           |
+--------------------+
| information_schema |
| mysql              |
| performance_schema |
| sys                |
+--------------------+
4 rows in set (0.00 sec)
```

## 创建数据库

```
mysql> CREATE DATABASE shop;
Query OK, 1 row affected (0.02 sec)

mysql> SHOW DATABASES;
+--------------------+
| Database           |
+--------------------+
| information_schema |
| mysql              |
| performance_schema |
| shop               |
| sys                |
+--------------------+
5 rows in set (0.04 sec)
```

## 选中使用数据库

```
mysql> USE shop;
Database changed
mysql>
```

## 创建表

ps：只能使用字母数字下划线命名

```
mysql> CREATE TABLE Product 
    -> (product_id CHAR(4) NOT NULL,
    -> product_name VARCHAR(100) NOT NULL,
    -> product_type VARCHAR(32) NOT NULL,
    -> sale_price INTEGER ,
    -> purchase_price INTEGER ,
    -> regist_date DATE ,
    -> PRIMARY KEY(product_id))
    -> ;
Query OK, 0 rows affected (0.03 sec)

mysql> SHOW TABLES;
+----------------+
| Tables_in_shop |
+----------------+
| Product        |
+----------------+
1 row in set (0.00 sec)

mysql>
```

ps:CHAR(8)不可变8位长度，输入'abc'，会以'abc '保存；VARCHAR可变

## 删除表

删了就无法恢复了

```
DROP TABLE shop;
```

## 添加表列

```
ALTER TABLE shop ADD COLUMN 列名;
```

## 删除列

```
ALTER TABLE shop DROP COLUMN 列名;
```

## 插入数据

```
START TRANSACTION;
INSERT INTO Product VALUES ('0001', 'T恤' ,'衣服', 1000, 500, '2009-09-20');
INSERT INTO Product VALUES ('0002', '打孔器', '办公用品', 500, 320, '2009-09-11');
INSERT INTO Product VALUES ('0003', '运动T恤', '衣服', 4000, 2800, NULL);
INSERT INTO Product VALUES ('0004', '菜刀', '厨房用具', 3000, 2800, '2009-09-20');
INSERT INTO Product VALUES ('0005', '高压锅', '厨房用具', 6800, 5000, '2009-01-15');
INSERT INTO Product VALUES ('0006', '叉子', '厨房用具', 500, NULL, '2009-09-20');
INSERT INTO Product VALUES ('0007', '擦菜板', '厨房用具', 880, 790, '2008-04-28');
INSERT INTO Product VALUES ('0008', '圆珠笔', '办公用品', 100, NULL, '2009-11-11');
COMMIT;

mysql> SELECT * FROM Product;
+------------+--------------+--------------+------------+----------------+-------------+
| product_id | product_name | product_type | sale_price | purchase_price | regist_date |
+------------+--------------+--------------+------------+----------------+-------------+
| 0001       | T恤          | 衣服         |       1000 |            500 | 2009-09-20  |
| 0002       | 打孔器       | 办公用品     |        500 |            320 | 2009-09-11  |
| 0003       | 运动T恤      | 衣服         |       4000 |           2800 | NULL        |
| 0004       | 菜刀         | 厨房用具     |       3000 |           2800 | 2009-09-20  |
| 0005       | 高压锅       | 厨房用具     |       6800 |           5000 | 2009-01-15  |
| 0006       | 叉子         | 厨房用具     |        500 |           NULL | 2009-09-20  |
| 0007       | 擦菜板       | 厨房用具     |        880 |            790 | 2008-04-28  |
| 0008       | 圆珠笔       | 办公用品     |        100 |           NULL | 2009-11-11  |
+------------+--------------+--------------+------------+----------------+-------------+
8 rows in set (0.00 sec)
```

## 修改表名

```
ALTER TABLE Product TO 表名;
```

## 退出

```
mysql> exit;
Bye
```


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