重拾SQL——从无到有

2016.10.22

因为工作需要，在这里提前重拾sql。

0.创建并选择数据库

mysql> SHOW DATABASES;

+--------------------+
| Database           |
+--------------------+
| information_schema |
| menagerie          |
| mysql              |
| performance_schema |
| phpmyadmin         |
| test               |
+--------------------+
6 rows in set (0.00 sec)

1.创建并选择数据库

mysql> CREATE DATABASE tianyuan;

Query OK, 1 row affected (0.00 sec)

2.查看创建后的数据库

mysql> SHOW DATABASES;

+--------------------+
| Database           |
+--------------------+
| information_schema |
| menagerie          |
| mysql              |
| performance_schema |
| phpmyadmin         |
| test               |
| tianyuan           |
+--------------------+
7 rows in set (0.00 sec)

3.访问它

mysql> USE tianyuan

Database changed

4.指定数据库中表的布局

mysql> CREATE TABLE pet (name VARCHAR(20), owner VARCHAR(20),
	-> species VARCHAR(20), sex CHAR(1), birth DATE, death DATE);

Query OK, 0 rows affected (0.14 sec)

5.显示表格

mysql> SHOW TABLES;

+--------------------+
| Tables_in_tianyuan |
+--------------------+
| pet                |
+--------------------+
1 row in set (0.00 sec)

6.验证表是按期望的方式创建（如果你忘记表中的列的名称或类型时）

mysql> DESCRIBE pet;

+---------+-------------+------+-----+---------+-------+
| Field   | Type        | Null | Key | Default | Extra |
+---------+-------------+------+-----+---------+-------+
| name    | varchar(20) | YES  |     | NULL    |       |
| owner   | varchar(20) | YES  |     | NULL    |       |
| species | varchar(20) | YES  |     | NULL    |       |
| sex     | char(1)     | YES  |     | NULL    |       |
| birth   | date        | YES  |     | NULL    |       |
| death   | date        | YES  |     | NULL    |       |
+---------+-------------+------+-----+---------+-------+
6 rows in set (0.01 sec)

7.选择表格所有列的内容（无内容时）

mysql> SELECT * FROM pet;

Empty set (0.00 sec)

8.将数据装入表中

• LOAD DATA

  mysql> LOAD DATA LOCAL INFILE '/Users/v/Desktop/1.txt' INTO TABLE pet;
  

  '/Users/v/Desktop/1.txt':

    Fluffy	Harold	cat	f	1993-02-04
    Claws	Gwen	cat	m	1994-03-17
    Buffy	Harold	dog	f	1989-05-13
    

  加载后

    Query OK, 3 rows affected, 3 warnings (0.07 sec)
    Records: 3  Deleted: 0  Skipped: 0  Warnings: 3
    

  查看

  mysql> SELECT * FROM pet;
  

    +--------+--------+---------+------+------------+-------+
    | name   | owner  | species | sex  | birth      | death |
    +--------+--------+---------+------+------------+-------+
    | Fluffy | Harold | cat     | f    | 1993-02-04 | NULL  |
    | Claws  | Gwen   | cat     | m    | 1994-03-17 | NULL  |
    | Buffy  | Harold | dog     | f    | 1989-05-13 | NULL  |
    +--------+--------+---------+------+------------+-------+
    3 rows in set (0.00 sec)
    

• INSERT

   mysql> INSERT INTO pet
   	-> VALUES ('Puffball','Diane','hamster','f','1999-03-30',NULL);
  

    Query OK, 1 row affected (0.05 sec)
    

  查看

  mysql> SELECT * FROM pet;
  

    +----------+--------+---------+------+------------+-------+
    | name     | owner  | species | sex  | birth      | death |
    +----------+--------+---------+------+------------+-------+
    | Fluffy   | Harold | cat     | f    | 1993-02-04 | NULL  |
    | Claws    | Gwen   | cat     | m    | 1994-03-17 | NULL  |
    | Buffy    | Harold | dog     | f    | 1989-05-13 | NULL  |
    | Puffball | Diane  | hamster | f    | 1999-03-30 | NULL  |
    +----------+--------+---------+------+------------+-------+
    4 rows in set (0.00 sec)
    

9.删除数据库

mysql> SHOW DATABASES;

+--------------------+
| Database           |
+--------------------+
| information_schema |
| menagerie          |
| mysql              |
| performance_schema |
| phpmyadmin         |
| test               |
| tianyuan           |
+--------------------+
7 rows in set (0.00 sec)

删除

mysql> DROP DATABASE test;

Query OK, 0 rows affected (0.02 sec)

查看删除效果

mysql> SHOW DATABASES;

+--------------------+
| Database           |
+--------------------+
| information_schema |
| menagerie          |
| mysql              |
| performance_schema |
| phpmyadmin         |
| tianyuan           |
+--------------------+
6 rows in set (0.00 sec)