mysql基础学习

发布时间:2016-11-21 11:01:15 阅读:782次

标红色为固定写法,熟记即可


登录mysql

mysql -uMysql服务器ip地址 -u用户名 -p密码

root@localhost ~ # mysql -uroot -p

Enter password:
Welcome to the MySQL monitor.  Commands end with ; or \g.
Your MySQL connection id is 12464
Server version: 5.1.60-log Source distribution
Type 'help;' or '\h' for help. Type '\c' to clear the buffer.

mysql>

显示所有数据库

mysql> show databases;
+--------------------+
| Database           |
+--------------------+
| information_schema |
| admin              |
| lnmpvideo          |
| mysql              |
| performance_schema |
| phpjx              |
| test               |
| yzcj               |
+--------------------+
8 rows in set (0.14 sec)
mysql>

创建数据库

mysql> create database xuexi;
Query OK, 1 row affected (0.06 sec)
mysql>

mysql> show databases;
+--------------------+
| Database           |
+--------------------+
| information_schema |
| admin              |
| lnmpvideo          |
| mysql              |
| performance_schema |
| phpjx              |
| test               |
| xuexi              | //刚才创建的数据库
| yzcj               |
+--------------------+
9 rows in set (0.00 sec)
mysql>

使用数据库

mysql> use xuexi;
Database changed
mysql>

显示所有表

mysql> show tables;
Empty set (0.00 sec)
mysql>

创建表study共4列

mysql> create table study(
    -> id int(11) auto_increment primary key,
    -> username varchar(50),
    -> sex enum('M','F'),
    -> addtime int(11)
    -> );
Query OK, 0 rows affected (0.08 sec)
mysql>

显示表

mysql> show tables;
+-----------------+
| Tables_in_xuexi |
+-----------------+
| study           |
+-----------------+
1 row in set (0.00 sec)
查询表的结构

mysql> desc study;
+----------+---------------+------+-----+---------+----------------+
| Field    | Type          | Null | Key | Default | Extra          |
+----------+---------------+------+-----+---------+----------------+
| id       | int(11)       | NO   | PRI | NULL    | auto_increment |
| username | varchar(50)   | YES  |     | NULL    |                |
| sex      | enum('M','F') | YES  |     | NULL    |                |
| addtime  | int(11)       | YES  |     | NULL    |                |
+----------+---------------+------+-----+---------+----------------+
4 rows in set (0.03 sec)
mysql>

添加数据每个逗号隔开的为一列或一个值,要列与值的数量匹配

mysql> insert into study values('','username1','M',unix_timestamp());
Query OK, 1 row affected, 1 warning (0.03 sec)
mysql> insert into study values('','username2','M',unix_timestamp());
Query OK, 1 row affected, 1 warning (0.00 sec)
mysql> insert into study(username,sex,addtime) values('username3','M',unix_timestamp());
Query OK, 1 row affected (0.00 sec)

如果不小心输入了单引号或者双引号,那么再次输入一个单引号或者双引号退出错误

mysql> select *from study1'
    '>  where
    '> id
    '> =1
    '>
    '>
    '>
    '> ';
ERROR 1064 (42000): You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near ''
 where
id
=1
'' at line 1
mysql>

查询表的所有数据

mysql> select *from study;
+----+-----------+------+------------+
| id | username  | sex  | addtime    |
+----+-----------+------+------------+
|  1 | username1 | M    | 1479697164 |
|  2 | username2 | M    | 1479697168 |
|  3 | username3 | M    | 1479697195 |
+----+-----------+------+------------+
3 rows in set (0.00 sec)

查询指定列的所有数据

mysql> select username,sex from study;
+-----------+------+
| username  | sex  |
+-----------+------+
| username1 | M    |
| username2 | M    |
| username3 | M    |
+-----------+------+
3 rows in set (0.00 sec)

查询username的值为username1的数据

mysql> select *from study where username='username1';
+----+-----------+------+------------+
| id | username  | sex  | addtime    |
+----+-----------+------+------------+
|  1 | username1 | M    | 1479697164 |
+----+-----------+------+------------+
1 row in set (0.00 sec)

使用时间函数

mysql> select *,from_unixtime(addtime) from study where username='username1';
+----+-----------+------+------------+------------------------+
| id | username  | sex  | addtime    | from_unixtime(addtime) |
+----+-----------+------+------------+------------------------+
|  1 | username1 | M    | 1479697164 | 2016-11-21 10:59:24    |
+----+-----------+------+------------+------------------------+
1 row in set (0.00 sec)
mysql>

查询username的值为username11的记录

mysql> select *from study where username='username11';
Empty set (0.00 sec)

更新

mysql> update study set username='username11' where username='username1';
Query OK, 1 row affected (0.00 sec)
Rows matched: 1  Changed: 1  Warnings: 0

查询

mysql> select *from study where username='username11';
+----+------------+------+------------+
| id | username   | sex  | addtime    |
+----+------------+------+------------+
|  1 | username11 | M    | 1479697164 |
+----+------------+------+------------+
1 row in set (0.00 sec)

删除

mysql> delete from study where username='username11';

Query OK, 1 row affected (0.00 sec)

显示

mysql> select *from study where username='username11';
Empty set (0.00 sec)
mysql>

结构修改

mysql> desc study;
+----------+---------------+------+-----+---------+----------------+
| Field    | Type          | Null | Key | Default | Extra          |
+----------+---------------+------+-----+---------+----------------+
| id       | int(11)       | NO   | PRI | NULL    | auto_increment |
| username | varchar(50)   | YES  |     | NULL    |                |
| sex      | enum('M','F') | YES  |     | NULL    |                |
| addtime  | int(11)       | YES  |     | NULL    |                |
+----------+---------------+------+-----+---------+----------------+
4 rows in set (0.00 sec)
添加一列

mysql> alter table study add test varchar(50) after sex;
Query OK, 2 rows affected (0.05 sec)
Records: 2  Duplicates: 0  Warnings: 0
mysql> desc study;
+----------+---------------+------+-----+---------+----------------+
| Field    | Type          | Null | Key | Default | Extra          |
+----------+---------------+------+-----+---------+----------------+
| id       | int(11)       | NO   | PRI | NULL    | auto_increment |
| username | varchar(50)   | YES  |     | NULL    |                |
| sex      | enum('M','F') | YES  |     | NULL    |                |
| test     | varchar(50)   | YES  |     | NULL    |                |
| addtime  | int(11)       | YES  |     | NULL    |                |
+----------+---------------+------+-----+---------+----------------+
5 rows in set (0.01 sec)
删除一列

mysql> alter table study drop test;
Query OK, 2 rows affected (0.01 sec)
Records: 2  Duplicates: 0  Warnings: 0
mysql> desc study;
+----------+---------------+------+-----+---------+----------------+
| Field    | Type          | Null | Key | Default | Extra          |
+----------+---------------+------+-----+---------+----------------+
| id       | int(11)       | NO   | PRI | NULL    | auto_increment |
| username | varchar(50)   | YES  |     | NULL    |                |
| sex      | enum('M','F') | YES  |     | NULL    |                |
| addtime  | int(11)       | YES  |     | NULL    |                |
+----------+---------------+------+-----+---------+----------------+
4 rows in set (0.00 sec)
mysql> alter table study add test varchar(50) after sex;

Query OK, 2 rows affected (0.01 sec)
Records: 2  Duplicates: 0  Warnings: 0
mysql> desc study;
+----------+---------------+------+-----+---------+----------------+
| Field    | Type          | Null | Key | Default | Extra          |
+----------+---------------+------+-----+---------+----------------+
| id       | int(11)       | NO   | PRI | NULL    | auto_increment |
| username | varchar(50)   | YES  |     | NULL    |                |
| sex      | enum('M','F') | YES  |     | NULL    |                |
| test     | varchar(50)   | YES  |     | NULL    |                |
| addtime  | int(11)       | YES  |     | NULL    |                |
+----------+---------------+------+-----+---------+----------------+
5 rows in set (0.01 sec)
修改列的列名和类型

mysql> alter table study change test test1 int(11);
Query OK, 2 rows affected (0.01 sec)
Records: 2  Duplicates: 0  Warnings: 0
mysql> desc study;
+----------+---------------+------+-----+---------+----------------+
| Field    | Type          | Null | Key | Default | Extra          |
+----------+---------------+------+-----+---------+----------------+
| id       | int(11)       | NO   | PRI | NULL    | auto_increment |
| username | varchar(50)   | YES  |     | NULL    |                |
| sex      | enum('M','F') | YES  |     | NULL    |                |
| test1    | int(11)       | YES  |     | NULL    |                |
| addtime  | int(11)       | YES  |     | NULL    |                |
+----------+---------------+------+-----+---------+----------------+
5 rows in set (0.01 sec)
mysql>

修改列的类型
mysql> alter table study modify test1 varchar(50);

Query OK, 2 rows affected (0.01 sec)
Records: 2  Duplicates: 0  Warnings: 0
mysql> desc study;
+----------+---------------+------+-----+---------+----------------+
| Field    | Type          | Null | Key | Default | Extra          |
+----------+---------------+------+-----+---------+----------------+
| id       | int(11)       | NO   | PRI | NULL    | auto_increment |
| username | varchar(50)   | YES  |     | NULL    |                |
| sex      | enum('M','F') | YES  |     | NULL    |                |
| test1    | varchar(50)   | YES  |     | NULL    |                |
| addtime  | int(11)       | YES  |     | NULL    |                |
+----------+---------------+------+-----+---------+----------------+
5 rows in set (0.00 sec)
mysql>

修改表名

mysql> alter table study rename studynew;
Query OK, 0 rows affected (0.00 sec)
mysql> show tables;
+-----------------+
| Tables_in_xuexi |
+-----------------+
| studynew        |
+-----------------+
1 row in set (0.00 sec)
mysql>

mysql日期操作

日期型例如:2016-11-22 17:13:20

时间戳例如:1479806000

mysql> select now();
+---------------------+
| now()               |
+---------------------+
| 2016-11-22 16:44:28 |
+---------------------+
1 row in set (0.00 sec)
mysql> select unix_timestamp();
+------------------+
| unix_timestamp() |
+------------------+
|       1479804287 |
+------------------+
1 row in set (0.00 sec)

mysql> select date(now());
+-------------+
| date(now()) |
+-------------+
| 2016-11-22  |
+-------------+
1 row in set (0.00 sec)

mysql> select unix_timestamp(now());
+-----------------------+
| unix_timestamp(now()) |
+-----------------------+
|            1479804353 |
+-----------------------+
1 row in set (0.00 sec)

mysql> select from_unixtime(unix_timestamp());
+---------------------------------+
| from_unixtime(unix_timestamp()) |
+---------------------------------+
| 2016-11-22 16:46:27             |
+---------------------------------+
1 row in set (0.01 sec)

mysql> select from_unixtime(unix_timestamp(now()));

+--------------------------------------+
| from_unixtime(unix_timestamp(now())) |
+--------------------------------------+
| 2016-11-22 16:46:48                  |
+--------------------------------------+

1 row in set (0.00 sec)

mysql> select year(date(now()));
+-------------------+
| year(date(now())) |
+-------------------+
|              2016 |
+-------------------+
1 row in set (0.00 sec)

mysql> select month(date(now()));
+--------------------+
| month(date(now())) |
+--------------------+
|                 11 |
+--------------------+
1 row in set (0.00 sec)

mysql> select day(date(now()));
+------------------+
| day(date(now())) |
+------------------+
|               22 |
+------------------+
1 row in set (0.00 sec)

mysql> select replace(link,substr(link,instr(link,"?"),100),'') from dh_minigw where type_id =1;

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