mysql> show variables like 'wait_timeout'; #查询连接超时

+---------------+-------+

| Variable_name | Value |

+---------------+-------+

| wait_timeout | 28800 |

+---------------+-------+

1 row in set (0.00 sec)

mysql> show processlist;# 查询连接表

+----+------+-----------+------+---------+------+----------+------------------+

| Id | User | Host | db | Command | Time | State | Info |

+----+------+-----------+------+---------+------+----------+------------------+

| 7 | root | localhost | NULL | Sleep | 2140 | | NULL |

| 9 | root | localhost | NULL | Sleep | 773 | | NULL |

| 10 | root | localhost | NULL | Query | 0 | starting | show processlist |

+----+------+-----------+------+---------+------+----------+------------------+

3 rows in set (0.00 sec)

mysql> show variables like 'query_cache_type'; # 查询缓存

+------------------+-------+

| Variable_name | Value |

+------------------+-------+

| query_cache_type | OFF |

+------------------+-------+

1 row in set (0.00 sec)

— 语法基础

mysql> create database `create_news`;# 创建数据库

Query OK, 1 row affected (0.00 sec)

mysql> use `create_news `;# 进入数据库

Database changed

mysql> show databases;# 查询数据库

+--------------------+

| Database |

+--------------------+

| information_schema |

| create_news |

| mysql |

| performance_schema |

| sys |

+--------------------+

5 rows in set (0.00 sec)

mysql> use create_news;# 进入数据库

Database changed

mysql> show tables;# 显示所有表

+-----------------------+

| Tables_in_create_news |

+-----------------------+

| news |

| news01 |

| news02 |

+-----------------------+

3 rows in set (0.00 sec)

mysql> desc news;# 显示表所有字段信息

+------------+---------------+------+-----+---------+----------------+

| Field | Type | Null | Key | Default | Extra |

+------------+---------------+------+-----+---------+----------------+

| id | int(11) | NO | PRI | NULL | auto_increment |

| title | varchar(200) | NO | | NULL | |

| content | varchar(2000) | NO | | NULL | |

| created_at | datetime | YES | | NULL | |

| types | varchar(10) | NO | | NULL | |

| images | varchar(300) | NO | | NULL | |

| autors | varchar(20) | NO | | NULL | |

| view_count | int(11) | YES | | 0 | |

| is_valid | smallint(6) | YES | | 1 | |

+------------+---------------+------+-----+---------+----------------+

9 rows in set (0.00 sec)

# 添加数据。语法 INSERT INTO table_name(字段) VALUES(值) (ps NOW()表示当前创建时间)

mysql> INSERT INTO news (

-> title,content,created_at,types,images,autors)

-> VALUES(

-> '天天Python','我要学习',NOW(),'新闻','not photo','lianwu');

Query OK, 1 row affected (0.00 sec)

# 查询数据。 语法 SELECT * form table_name WHERE 添加。 (ps *表示所有字段 WHERE条件不设置表示显示所有信息列表)

mysql> SELECT * from news WHERE id >20;

+----+--------------+--------------+---------------------+--------+-----------+--------+------------+----------+

| id | title | content | created_at | types | images | autors | view_count | is_valid |

+----+--------------+--------------+---------------------+--------+-----------+--------+------------+----------+

| 29 | 天天Python | 我要学习 | 2020-08-23 20:59:39 | 新闻 | not photo | lianwu | 0 | 1 |

| 30 | 天天Python | 我要学习 | 2020-08-23 21:00:00 | 新闻 | not photo | lianwu | 0 | 1 |

+----+--------------+--------------+---------------------+--------+-----------+--------+------------+----------+

2 rows in set (0.00 sec)