码迷,mamicode.com
首页 > 其他好文 > 详细

库操作和表操作

时间:2018-09-28 12:37:41      阅读:134      评论:0      收藏:0      [点我收藏+]

标签:set   ORC   client   myisam   last   一个   esc   char   use   

一、库操作

 

1.新建数据库

语法:
create database 数据库名 charset utf8;

mysql> create database gao1 charset utf8;
Query OK, 1 row affected (0.00 sec)

 

2.查看数据库

 

查看所有的库:show databases;

show databases;


mysql> show databases;
+--------------------+
| Database           |
+--------------------+
| information_schema |
| gao                |
| gao1               |
| mysql              |
| performance_schema |
| sys                |
+--------------------+
6 rows in set (0.01 sec)

 

具体查看某个库:show create database 数据库名

mysql> show create database gao1;
+----------+---------------------------------------------------------------+
| Database | Create Database                                               |
+----------+---------------------------------------------------------------+
| gao1     | CREATE DATABASE `gao1` /*!40100 DEFAULT CHARACTER SET utf8 */ |
+----------+---------------------------------------------------------------+
1 row in set (0.00 sec)

 

查看当前所在的库:select database();

mysql> use gao1
Database changed
mysql> select database();
+------------+
| database() |
+------------+
| gao1       |
+------------+
1 row in set (0.00 sec)

 

3.使用库

use 数据库名

mysql> use gao
Database changed
mysql> select database();
+------------+
| database() |
+------------+
| gao        |
+------------+
1 row in set (0.00 sec)

 

4.删除数据库

drop database  数据库名;

mysql> drop database gao1;
Query OK, 0 rows affected (0.01 sec)

mysql> show databases;
+--------------------+
| Database           |
+--------------------+
| information_schema |
| gao                |
| mysql              |
| performance_schema |
| sys                |
+--------------------+
5 rows in set (0.00 sec)

 

5.修改数据库

alter database 数据库名 charset 编码名

mysql> alter database gao charset gbk;
Query OK, 1 row affected (0.00 sec)

mysql> show create database gao;
+----------+-------------------------------------------------------------+
| Database | Create Database                                             |
+----------+-------------------------------------------------------------+
| gao      | CREATE DATABASE `gao` /*!40100 DEFAULT CHARACTER SET gbk */ |
+----------+-------------------------------------------------------------+
1 row in set (0.00 sec)

 

二、表操作

 

1、创建表

格式:

create table(

字段名1  类型[宽度,约束类型],

字段名2 类型[宽度,约束类型],

字段名3 类型[宽度,约束类型],

);

 

注意点:

1、同一个表中,字段名不能相同

2、宽度和约束类型是自己选择的

3、字段名和类型是必须的

 

mysql> use gao
Database changed
mysql> create table intforce(
    -> id int,
    -> name varchar(50),
    -> age int(3)
    -> );
Query OK, 0 rows affected (0.04 sec)

mysql> show tables;
+---------------+
| Tables_in_gao |
+---------------+
| intforce      |
| t1            |
| t2            |
| t3            |
| t4            |
| t5            |
| t6            |
+---------------+
7 rows in set (0.00 sec)

mysql> desc intforce
    -> ;
+-------+-------------+------+-----+---------+-------+
| Field | Type        | Null | Key | Default | Extra |
+-------+-------------+------+-----+---------+-------+
| id    | int(11)     | YES  |     | NULL    |       |
| name  | varchar(50) | YES  |     | NULL    |       |
| age   | int(3)      | YES  |     | NULL    |       |
+-------+-------------+------+-----+---------+-------+
3 rows in set (0.02 sec)

 

2.查看表

show create table 表名; \G 可查看表详细结构

1、在当前数据库下

mysql> show create table intforce;
+----------+-----------------------------------------------------------------------------------------------------------------------------------------------------------+
| Table    | Create Table                                                                                                                                              |
+----------+-----------------------------------------------------------------------------------------------------------------------------------------------------------+
| intforce | CREATE TABLE `intforce` (
  `id` int(11) DEFAULT NULL,
  `name` varchar(50) DEFAULT NULL,
  `age` int(3) DEFAULT NULL
) ENGINE=InnoDB DEFAULT CHARSET=gbk |
+----------+-----------------------------------------------------------------------------------------------------------------------------------------------------------+
1 row in set (0.00 sec)

 

2、在其他数据库下

[mysql> show create table mysql.user;
+-------+-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+
| Table | Create Table                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                     |
+-------+-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+
| user  | CREATE TABLE `user` (
  `Host` char(60) COLLATE utf8_bin NOT NULL DEFAULT ‘‘,
  `User` char(32) COLLATE utf8_bin NOT NULL DEFAULT ‘‘,
  `Select_priv` enum(N,Y) CHARACTER SET utf8 NOT NULL DEFAULT N,
  `Insert_priv` enum(N,Y) CHARACTER SET utf8 NOT NULL DEFAULT N,
  `Update_priv` enum(N,Y) CHARACTER SET utf8 NOT NULL DEFAULT N,
  `Delete_priv` enum(N,Y) CHARACTER SET utf8 NOT NULL DEFAULT N,
  `Create_priv` enum(N,Y) CHARACTER SET utf8 NOT NULL DEFAULT N,
  `Drop_priv` enum(N,Y) CHARACTER SET utf8 NOT NULL DEFAULT N,
  `Reload_priv` enum(N,Y) CHARACTER SET utf8 NOT NULL DEFAULT N,
  `Shutdown_priv` enum(N,Y) CHARACTER SET utf8 NOT NULL DEFAULT N,
  `Process_priv` enum(N,Y) CHARACTER SET utf8 NOT NULL DEFAULT N,
  `File_priv` enum(N,Y) CHARACTER SET utf8 NOT NULL DEFAULT N,
  `Grant_priv` enum(N,Y) CHARACTER SET utf8 NOT NULL DEFAULT N,
  `References_priv` enum(N,Y) CHARACTER SET utf8 NOT NULL DEFAULT N,
  `Index_priv` enum(N,Y) CHARACTER SET utf8 NOT NULL DEFAULT N,
  `Alter_priv` enum(N,Y) CHARACTER SET utf8 NOT NULL DEFAULT N,
  `Show_db_priv` enum(N,Y) CHARACTER SET utf8 NOT NULL DEFAULT N,
  `Super_priv` enum(N,Y) CHARACTER SET utf8 NOT NULL DEFAULT N,
  `Create_tmp_table_priv` enum(N,Y) CHARACTER SET utf8 NOT NULL DEFAULT N,
  `Lock_tables_priv` enum(N,Y) CHARACTER SET utf8 NOT NULL DEFAULT N,
  `Execute_priv` enum(N,Y) CHARACTER SET utf8 NOT NULL DEFAULT N,
  `Repl_slave_priv` enum(N,Y) CHARACTER SET utf8 NOT NULL DEFAULT N,
  `Repl_client_priv` enum(N,Y) CHARACTER SET utf8 NOT NULL DEFAULT N,
  `Create_view_priv` enum(N,Y) CHARACTER SET utf8 NOT NULL DEFAULT N,
  `Show_view_priv` enum(N,Y) CHARACTER SET utf8 NOT NULL DEFAULT N,
  `Create_routine_priv` enum(N,Y) CHARACTER SET utf8 NOT NULL DEFAULT N,
  `Alter_routine_priv` enum(N,Y) CHARACTER SET utf8 NOT NULL DEFAULT N,
  `Create_user_priv` enum(N,Y) CHARACTER SET utf8 NOT NULL DEFAULT N,
  `Event_priv` enum(N,Y) CHARACTER SET utf8 NOT NULL DEFAULT N,
  `Trigger_priv` enum(N,Y) CHARACTER SET utf8 NOT NULL DEFAULT N,
  `Create_tablespace_priv` enum(N,Y) CHARACTER SET utf8 NOT NULL DEFAULT N,
  `ssl_type` enum(‘‘,ANY,X509,SPECIFIED) CHARACTER SET utf8 NOT NULL DEFAULT ‘‘,
  `ssl_cipher` blob NOT NULL,
  `x509_issuer` blob NOT NULL,
  `x509_subject` blob NOT NULL,
  `max_questions` int(11) unsigned NOT NULL DEFAULT 0,
  `max_updates` int(11) unsigned NOT NULL DEFAULT 0,
  `max_connections` int(11) unsigned NOT NULL DEFAULT 0,
  `max_user_connections` int(11) unsigned NOT NULL DEFAULT 0,
  `plugin` char(64) COLLATE utf8_bin NOT NULL DEFAULT mysql_native_password,
  `authentication_string` text COLLATE utf8_bin,
  `password_expired` enum(N,Y) CHARACTER SET utf8 NOT NULL DEFAULT N,
  `password_last_changed` timestamp NULL DEFAULT NULL,
  `password_lifetime` smallint(5) unsigned DEFAULT NULL,
  `account_locked` enum(N,Y) CHARACTER SET utf8 NOT NULL DEFAULT N,
  PRIMARY KEY (`Host`,`User`)
) ENGINE=MyISAM DEFAULT CHARSET=utf8 COLLATE=utf8_bin COMMENT=Users and global privileges |
+-------+-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+
1 row in set (0.01 sec)

 

3、修改表结构

1、修改表名

alter table 表名 rename 新表名

如下图把表test1 改成 test2

mysql> show tables;
+---------------+
| Tables_in_gao |
+---------------+
| t1            |
| t2            |
| t3            |
| t4            |
| t5            |
| t6            |
| test1         |
+---------------+
7 rows in set (0.00 sec)

mysql> alter table test1 rename test2;
Query OK, 0 rows affected (0.00 sec)

mysql> show tables;
+---------------+
| Tables_in_gao |
+---------------+
| t1            |
| t2            |
| t3            |
| t4            |
| t5            |
| t6            |
| test2         |
+---------------+
7 rows in set (0.00 sec)

 

2、增加字段

alter table 表名 add 字段名 数据类型 【约束条件】

        add 字段名 数据类型 【约束条件】 

                      add 字段名 数据类型 【约束条件】

mysql> alter table test2
    -> add money int(4) not null default 10,
    -> add place varchar(10) not null
    -> ;

mysql> desc test2;
+-------+-------------+------+-----+---------+-------+
| Field | Type        | Null | Key | Default | Extra |
+-------+-------------+------+-----+---------+-------+
| id    | int(11)     | YES  |     | NULL    |       |
| name  | varchar(50) | YES  |     | NULL    |       |
| age   | int(3)      | YES  |     | NULL    |       |
| money | int(4)      | NO   |     | 10      |       |
| place | varchar(10) | NO   |     | NULL    |       |
+-------+-------------+------+-----+---------+-------+
5 rows in set (0.01 sec)

 

添加在某个字段后面

mysql> alter table test2
    -> add stu_name varchar(10) after name;
Query OK, 0 rows affected (0.03 sec)
Records: 0  Duplicates: 0  Warnings: 0

mysql> desc test2;
+----------+-------------+------+-----+---------+-------+
| Field    | Type        | Null | Key | Default | Extra |
+----------+-------------+------+-----+---------+-------+
| id       | int(11)     | YES  |     | NULL    |       |
| name     | varchar(50) | YES  |     | NULL    |       |
| stu_name | varchar(10) | YES  |     | NULL    |       |
| age      | int(3)      | YES  |     | NULL    |       |
| money    | int(4)      | NO   |     | 10      |       |
| place    | varchar(10) | NO   |     | NULL    |       |
+----------+-------------+------+-----+---------+-------+
6 rows in set (0.01 sec)

 

把字段加在第一个

mysql> alter table test2
    -> add stu_age int(2) first;
Query OK, 0 rows affected (0.03 sec)
Records: 0  Duplicates: 0  Warnings: 0

mysql> desc test2;
+----------+-------------+------+-----+---------+-------+
| Field    | Type        | Null | Key | Default | Extra |
+----------+-------------+------+-----+---------+-------+
| stu_age  | int(2)      | YES  |     | NULL    |       |
| id       | int(11)     | YES  |     | NULL    |       |
| name     | varchar(50) | YES  |     | NULL    |       |
| stu_name | varchar(10) | YES  |     | NULL    |       |
| age      | int(3)      | YES  |     | NULL    |       |
| money    | int(4)      | NO   |     | 10      |       |
| place    | varchar(10) | NO   |     | NULL    |       |
+----------+-------------+------+-----+---------+-------+
7 rows in set (0.00 sec)

 

3.删除字段

alter table 表名 drop 字段名

删除stu_age 字段

mysql> alter table test2
    -> drop stu_age;
Query OK, 0 rows affected (0.06 sec)
Records: 0  Duplicates: 0  Warnings: 0

mysql> desc test2;
+----------+-------------+------+-----+---------+-------+
| Field    | Type        | Null | Key | Default | Extra |
+----------+-------------+------+-----+---------+-------+
| id       | int(11)     | YES  |     | NULL    |       |
| name     | varchar(50) | YES  |     | NULL    |       |
| stu_name | varchar(10) | YES  |     | NULL    |       |
| age      | int(3)      | YES  |     | NULL    |       |
| money    | int(4)      | NO   |     | 10      |       |
| place    | varchar(10) | NO   |     | NULL    |       |
+----------+-------------+------+-----+---------+-------+
6 rows in set (0.00 sec)

 

4.修改字段

把id的类型改为int(8)

mysql> alter table test2
    -> modify id int(8);
Query OK, 0 rows affected (0.03 sec)
Records: 0  Duplicates: 0  Warnings: 0

mysql> desc test2;
+----------+-------------+------+-----+---------+-------+
| Field    | Type        | Null | Key | Default | Extra |
+----------+-------------+------+-----+---------+-------+
| id       | int(8)      | YES  |     | NULL    |       |
| name     | varchar(50) | YES  |     | NULL    |       |
| stu_name | varchar(10) | YES  |     | NULL    |       |
| age      | int(3)      | YES  |     | NULL    |       |
| money    | int(4)      | NO   |     | 10      |       |
| place    | varchar(10) | NO   |     | NULL    |       |
+----------+-------------+------+-----+---------+-------+
6 rows in set (0.00 sec)

 

5.复制一个表

结构和数据都有

新建一个和test2一样的test1表

mysql> create table test1 select * from test2;
Query OK, 0 rows affected (0.03 sec)
Records: 0  Duplicates: 0  Warnings: 0

mysql> show tables;
+---------------+
| Tables_in_gao |
+---------------+
| t1            |
| t2            |
| t3            |
| t4            |
| t5            |
| t6            |
| test1         |
| test2         |
+---------------+
8 rows in set (0.00 sec)

 

只有表结构不需要数据

方法1:

create table 新表名 like 老表名

mysql> select * from test2;
+------+------+----------+------+-------+-------+
| id   | name | stu_name | age  | money | place |
+------+------+----------+------+-------+-------+
| NULL | gao  | NULL     |   20 |    10 | aa    |
+------+------+----------+------+-------+-------+
1 row in set (0.00 sec)

mysql> create table test3 like test1;
Query OK, 0 rows affected (0.03 sec)

mysql> select * from test3;
Empty set (0.00 sec)

方法二:

create table 新表名 select * from 旧表名 where 1=2;  ##条件为假 查不到任何记录

mysql> show tables;
+---------------+
| Tables_in_gao |
+---------------+
| t1            |
| t2            |
| t3            |
| t4            |
| t5            |
| t6            |
| test1         |
| test2         |
| test3         |
+---------------+
9 rows in set (0.00 sec)

mysql> create table test4 select * from test1 where 1=2;
Query OK, 0 rows affected (0.02 sec)
Records: 0  Duplicates: 0  Warnings: 0

mysql> select * from test4;
Empty set (0.00 sec)

 

6.删除表

删除表test5

mysql> show tables;
+---------------+
| Tables_in_gao |
+---------------+
| t1            |
| t2            |
| t3            |
| t4            |
| t5            |
| t6            |
| test1         |
| test2         |
| test3         |
| test5         |
+---------------+
10 rows in set (0.00 sec)

mysql> drop table test5
    -> ;
Query OK, 0 rows affected (0.01 sec)

mysql> show tables;
+---------------+
| Tables_in_gao |
+---------------+
| t1            |
| t2            |
| t3            |
| t4            |
| t5            |
| t6            |
| test1         |
| test2         |
| test3         |
+---------------+
9 rows in set (0.00 sec)

 

库操作和表操作

标签:set   ORC   client   myisam   last   一个   esc   char   use   

原文地址:https://www.cnblogs.com/huizaia/p/9711461.html

(0)
(0)
   
举报
评论 一句话评论(0
登录后才能评论!
© 2014 mamicode.com 版权所有  联系我们:gaon5@hotmail.com
迷上了代码!