首页 > 技术文章 > 重拾SQL——从无到有

thqy39 2016-11-02 17:48 原文

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)

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