1. 登录mysql
mysql -u root -p 然后输入密码
2， 查看已有数据库
mysql> show databases;
+--------------------+
| Database |
+--------------------+
| information_schema |
| codeigniter |
| mysql |
| spam |
| test |
+--------------------+
然后进入一个数据库：
mysql> use test
Database changed
现在就进入test数据库了，然后显示这个数据库中的所有表：
mysql> show tables;
+-----------------------+
| Tables_in_codeigniter |
+-----------------------+
| bey_sessions |
| migrations |
| problems |
| replies |
| solutions |
| tokens |
| topics |
| userinfos |
| users |
| vips |
+-----------------------+
10 rows in set (0.00 sec)
查看表的数据结构：
mysql> desc users;
+----------+------------------------+------+-----+---------+----------------+
| Field | Type | Null | Key | Default | Extra |
+----------+------------------------+------+-----+---------+----------------+
| id | mediumint(11) unsigned | NO | PRI | NULL | auto_increment |
| username | varchar(100) | NO | | NULL | |
| password | varchar(80) | NO | | NULL | |
| email | varchar(100) | YES | | NULL | |
| status | tinyint(1) unsigned | NO | | 0 | |
+----------+------------------------+------+-----+---------+----------------+
3. 插入一条记录；
mysql> insert into users values(null, 'ceshiyonghu', '111', '110000@qq.com ', '1');
Query OK, 1 row affected (0.01 sec)
插入某个字段
mysql> insert into users (id, username) values (null, 'liu');
Query OK, 1 row affected, 1 warning (0.00 sec)
4. 查询记录：
mysql> select * from users;
+-------+-------------+------------------------------------------------------------------+---------------+--------+
| id | username | password | email | status |
+-------+-------------+------------------------------------------------------------------+---------------+--------+
| 10005 | ??134 | ccb797aae770710012a7b0e5834e7ee5c1994f80a31bc86332b96e1c90015cea | 0 | 0 |
| 10006 | ???? | 31ed43c7ba20fa7b2600b200b064de3c7cdbafe0c32019101daf93203c8ac27b | NULL | 0 |
| 10007 | ceshiyonghu | 111 | 110000@qq.com | 1 |
| 10008 | liu | | NULL | 0 |
+-------+-------------+------------------------------------------------------------------+---------------+--------+
查询某个字段
mysql> select id, username from users;
+-------+-------------+
| id | username |
+-------+-------------+
| 10005 | ??134 |
| 10006 | ???? |
| 10007 | ceshiyonghu |
| 10008 | liu |
+-------+-------------+
4 rows in set (0.00 sec)
5. 更新某个字段
mysql> update users set username = 'liu2' where id = 10008;
Query OK, 1 row affected (0.00 sec)
where语句用来定位某几行
mysql> select * from users;
+-------+-------------+------------------------------------------------------------------+---------------+--------+
| id | username | password | email | status |
+-------+-------------+------------------------------------------------------------------+---------------+--------+
| 10005 | ??134 | ccb797aae770710012a7b0e5834e7ee5c1994f80a31bc86332b96e1c90015cea | 0 | 0 |
| 10006 | ???? | 31ed43c7ba20fa7b2600b200b064de3c7cdbafe0c32019101daf93203c8ac27b | NULL | 0 |
| 10007 | ceshiyonghu | 111 | 110000@qq.com | 1 |
| 10008 | liu2 | | NULL | 0 |
+-------+-------------+------------------------------------------------------------------
更新多个字段
mysql> update users set username = 'liu2' , password = '222' where id = 10008;
Query OK, 1 row affected (0.00 sec)
mysql> select * from users;
+-------+-------------+------------------------------------------------------------------+---------------+--------+
| id | username | password | email | status |
+-------+-------------+------------------------------------------------------------------+---------------+--------+
| 10005 | ??134 | ccb797aae770710012a7b0e5834e7ee5c1994f80a31bc86332b96e1c90015cea | 0 | 0 |
| 10006 | ???? | 31ed43c7ba20fa7b2600b200b064de3c7cdbafe0c32019101daf93203c8ac27b | NULL | 0 |
| 10007 | ceshiyonghu | 111 | 110000@qq.com | 1 |
| 10008 | liu2 | 222 | NULL | 0 |
+-------+-------------+------------------------------------------------------------------+---------------+--------+
6. 删除记录：
mysql> delete from users where id = 10008;
Query OK, 1 row affected (0.00 sec)
mysql> select * from users;
+-------+-------------+------------------------------------------------------------------+---------------+--------+
| id | username | password | email | status |
+-------+-------------+------------------------------------------------------------------+---------------+--------+
| 10005 | ??134 | ccb797aae770710012a7b0e5834e7ee5c1994f80a31bc86332b96e1c90015cea | 0 | 0 |
| 10006 | ???? | 31ed43c7ba20fa7b2600b200b064de3c7cdbafe0c32019101daf93203c8ac27b | NULL | 0 |
| 10007 | ceshiyonghu | 111 | 110000@qq.com | 1 |
+-------+-------------+------------------------------------------------------------------+---------------+--------+