mysql基础学习

目录

  • 安装mysql服务器
    • 查看系统版本
    • 开始安装mysql
    • 查看是否安装成功
    • 启动mysql
  • mysql学习
    • DDL 定义语言 (CREATE/DROP/ALTER)
    • DML 操作语言(INSERT/UPDATE/DELETE)
    • DQL 查询语言(SELECT)
    • DCL 控制语言(GRANT/REVOKE/COMMIT/ROLLBACK)

1.安装mysql服务器
  1.1 查看系统版本

yan@yan:~$ cat /etc/issue
Ubuntu 16.10 \n \l

yan@yan:~$ cat /etc/issue.net 
Ubuntu 16.10
yan@yan:~$ uname -a
Linux yan 4.8.0-22-generic #24-Ubuntu SMP Sat Oct 8 09:14:42 UTC 2016 i686 i686 i686 GNU/Linux
yan@yan:~$

  

  1.2 开始安装mysql

root@yan:~# apt-get install mysql-server
root@yan:~# apt-get install mysql-client
root@yan:~# apt-get install libmysqlclient-dev

  注意:安装software时,一定要是root用户登录哟,否则会报错(没有权限)

  1.3 查看是否安装成功

root@yan:~# [ `ps aux | grep mysql | grep -v "grep" | wc -l` -ge 0 ] && echo -e "Install OK" || echo -e "Install fail"

  如果提示Install OK 则表示有进程 如果提示Install fail 则可能需要自己重新启动一下程序了
  重启命令:root@yan:~# /etc/init.d/mysql restart

  

  1.4 启动mysql

root@yan:~# mysql -uroot -p

  其中:mysql 代表mysql程序 -u代表USER -p 代表password
  综合起来就是:使用root用户(mysql用户和系统用户是两码事)来登录mysql并且有密码

2.mysql学习

  2.1 DDL 定义语言 (主要讲三个:CREATE/DROP/ALTER)
  新建数据库(新建了一个数据库,其名称为yan)

mysql> CREATE DATABASE yan;
Query OK, 1 row affected (0.00 sec)

  查看数据库(可见,yan已经创建成功了)

mysql> SHOW DATABASES;
+--------------------+
| Database |
+--------------------+
| information_schema |
| mysql |
| performance_schema |
| sys |
| yan |
+--------------------+
5 rows in set (0.00 sec)

  

  查看建库语句

mysql> SHOW CREATE DATABASE yan;
+----------+----------------------------------------------------------------+
| Database | Create Database |
+----------+----------------------------------------------------------------+
| yan | CREATE DATABASE `yan` /*!40100 DEFAULT CHARACTER SET latin1 */ |
+----------+----------------------------------------------------------------+
1 row in set (0.00 sec)

mysql>

  删除数据库

mysql> DROP DATABASE yan;
Query OK, 0 rows affected (0.00 sec)

  再次检查数据库(可见,yan这个数据库已经没有了)

  新建数据表
  需求:
  新建一个购物清单表

  新建数据库yan

mysql> CREATE DATABASE yan;
Query OK, 1 row affected (0.00 sec)

  设置为默认数据库

mysql> USE yan;
Database changed

  新建表shopping_info

mysql> CREATE TABLE shopping_info (
-> id INT(11) AUTO_INCREMENT,
-> invoice INT(30) NOT NULL UNIQUE,
-> name VARCHAR(50) NOT NULL,
-> price FLOAT NOT NULL,
-> PRIMARY KEY(id)
-> );
Query OK, 0 rows affected (0.33 sec)

再新建一个收据表

  新建表receipt_info

mysql> CREATE TABLE receipt_info (
-> id INT(11) AUTO_INCREMENT,
-> date date NOT NULL,
-> CONSTRAINT fk FOREIGN KEY(id) REFERENCES shopping_info(id)
-> );
Query OK, 0 rows affected (0.97 sec)

mysql>

  再新建一个数据表

mysql> CREATE TABLE user_info (
-> id VARCHAR(50) UNIQUE NOT NULL,
-> name VARCHAR(50) NOT NULL,
-> price FLOAT NOT NULL DEFAULT 0,
-> age INT(10) NOT NULL DEFAULT 0
-> );
Query OK, 0 rows affected (0.34 sec)

mysql>

  ALTER
  现在将表user_info更改为user_infomation

mysql> ALTER TABLE user_info RENAME user_information;
Query OK, 0 rows affected (0.14 sec)

  修改数据类型,先将price中的FLOAT数据类型修改为DOUBLE类型

mysql> ALTER TABLE user_information MODIFY price DOUBLE;
Query OK, 0 rows affected (0.74 sec)
Records: 0 Duplicates: 0 Warnings: 0

mysql>

  添加字段English_name至表user_info,位于最前面

mysql> ALTER TABLE user_information ADD english_name VARCHAR(20) NOT NULL FIRST;
Query OK, 0 rows affected (0.49 sec)
Records: 0 Duplicates: 0 Warnings: 0

  添加字段English_name1至表user_info,位于name后面

mysql> ALTER TABLE user_information ADD english_name_1 VARCHAR(20) NOT NULL AFTER name;
Query OK, 0 rows affected (0.62 sec)
Records: 0 Duplicates: 0 Warnings: 0

  删除字段 现在将english_name_1这个字段给删除掉

mysql> ALTER TABLE user_information DROP english_name_1;
Query OK, 0 rows affected (0.48 sec)
Records: 0 Duplicates: 0 Warnings: 0

  修改字段排序,现在将age这个字段给提到第一

mysql> ALTER TABLE user_information MODIFY age INT(10) NOT NULL DEFAULT 0 FIRST;
Query OK, 0 rows affected (0.44 sec)
Records: 0 Duplicates: 0 Warnings: 0

  删除receipt_info的外键约束

mysql> ALTER TABLE receipt_info DROP FOREIGN KEY fk;
Query OK, 0 rows affected (0.08 sec)
Records: 0 Duplicates: 0 Warnings: 0

  删除数据表shopping_info

mysql> DROP TABLE shopping_info;
Query OK, 0 rows affected (0.21 sec)

  2.2 DML 操作语言(INSERT/UPDATE/DELETE)
  INSERT:
  1.向user_information这个表插入数据

mysql> INSERT INTO user_information VALUES (21,'Ming',112,'ming',12.5);
Query OK, 1 row affected (0.04 sec)

  2.插入部门内容

mysql> INSERT INTO user_information (id,age,english_name,name) VALUES (113,22,'kun','Skun');
Query OK, 1 row affected (0.04 sec)

  3.利用单引号来转意

mysql> INSERT INTO user_information VALUES (13,'xuzhneg''s',123345,'zheng''s',123.5);
Query OK, 1 row affected (0.05 sec)

  UPDATE:
  1.修改user_information中age=21的user_information的name值,修改为Li

mysql> UPDATE user_information
-> SET name='li'
-> WHERE age=21;
Query OK, 1 row affected (0.09 sec)
Rows matched: 1 Changed: 1 Warnings: 0

  2.多表更新操作
  现向表receipt_info插入信息

mysql> INSERT INTO receipt_info VALUES (112,'2017-3-27');
Query OK, 1 row affected (0.04 sec)

  多表更新,设置receipt.id的值,其中条件为receipt_info.id等于user_information.id的值

mysql> UPDATE receipt_info,user_information
-> SET user_information.age=100
-> WHERE receipt_info.id=user_information.id;
Query OK, 1 row affected (0.05 sec)
Rows matched: 1 Changed: 1 Warnings: 0

  DELETE:
  1.删除表receipt中id为112的数据

mysql> DELETE FROM receipt_info WHERE id=112;
Query OK, 1 row affected (0.04 sec)

  2.多表删除数据
  现向表receipt_info插入信息

mysql> INSERT INTO receipt_info VALUES (112,'2017-3-27');
Query OK, 1 row affected (0.04 sec)

  删除user_information和receipt_info表中id相等的字段

mysql> DELETE receipt_info,user_information FROM user_informatiipt_info on,receWHERE user_information.ipt_info.id;
Query OK, 2 rows affected (0.04 sec)

  2.3 DQL 查询语言(SELECT)
  1.简单查询、查询user_information表中所有数据

mysql> SELECT * FROM user_information;
+-----+--------------+--------+---------+-------+
| age | english_name | id | name | price |
+-----+--------------+--------+---------+-------+
| 22 | kun | 113 | Skun | NULL |
| 13 | xuzhneg's | 123345 | zheng's | 123.5 |
+-----+--------------+--------+---------+-------+
2 rows in set (0.00 sec)

  2.根据条件查询、查询user_information表中age等于22的数据

mysql> SELECT * FROM user_information WHERE age=22;
+-----+--------------+-----+------+-------+
| age | english_name | id | name | price |
+-----+--------------+-----+------+-------+
| 22 | kun | 113 | Skun | NULL |
+-----+--------------+-----+------+-------+
1 row in set (0.00 sec)

  3.条件查询user_information表中price为NULL值的数据

mysql> SELECT * FROM user_information WHERE price is NULL;
+-----+--------------+-----+------+-------+
| age | english_name | id | name | price |
+-----+--------------+-----+------+-------+
| 22 | kun | 113 | Skun | NULL |
+-----+--------------+-----+------+-------+
1 row in set (0.00 sec)

  4.查询user_information中的数据,并且对age进行排序

mysql> SELECT * FROM user_information ORDER BY age;
+-----+--------------+--------+---------+-------+
| age | english_name | id | name | price |
+-----+--------------+--------+---------+-------+
| 13 | xuzhneg's | 123345 | zheng's | 123.5 |
| 22 | kun | 113 | Skun | NULL |
+-----+--------------+--------+---------+-------+
2 rows in set (0.00 sec)

  5.查询user_information中的数据,并且对age进行排序,且只输入1行

mysql> SELECT * FROM user_information ORDER BY age LIMIT 1;
+-----+--------------+--------+---------+-------+
| age | english_name | id | name | price |
+-----+--------------+--------+---------+-------+
| 13 | xuzhneg's | 123345 | zheng's | 123.5 |
+-----+--------------+--------+---------+-------+
1 row in set (0.00 sec)

  6.模糊匹配、查询user_information中的数据且Name是以z开头的字符串

mysql> SELECT * FROM user_information WHERE name like 'z%';
+-----+--------------+--------+---------+-------+
| age | english_name | id | name | price |
+-----+--------------+--------+---------+-------+
| 13 | xuzhneg's | 123345 | zheng's | 123.5 |
+-----+--------------+--------+---------+-------+
1 row in set (0.00 sec)

  7.模糊匹配、匹配user_information中的id含1的信息

mysql> SELECT * FROM user_information WHERE id like '%1%';
+-----+--------------+--------+---------+-------+
| age | english_name | id | name | price |
+-----+--------------+--------+---------+-------+
| 22 | kun | 113 | Skun | NULL |
| 13 | xuzhneg's | 123345 | zheng's | 123.5 |
+-----+--------------+--------+---------+-------+
2 rows in set (0.00 sec)

  2.4 DCL 控制语言(GRANT/REVOKE/COMMIT/ROLLBACK)

欢迎转发! 请保留源地址: https://www.cnblogs.com/NoneID
原文地址:https://www.cnblogs.com/NoneID/p/6629402.html