MySQL终端（Terminal）命令基本操做（转）

时间 2019-11-18

原文原文链接

注意：MySQL数据库命令不区分大小写。但在MAC的终端，若是你想使用tab自动补全命令，那么你就必须使用大写，这样MAC的终端才会帮你补全命令，不然你按N遍tab都不会有响应。html

一、数据库（database）管理mysql

1.一、create建立数据库sql

create database firstDB;

1.二、show查看全部数据库数据库

mysql> show databases;

+--------------------+
| Database           |
+--------------------+
| information_schema |
| firstDB            |
| mysql              |
| performance_schema |
+--------------------+
4 rows in set (0.00 sec)

1.三、alter修改数据库编码

alter命令修改数据库编码：code

默认建立的数据库默认不支持中文字符，若是咱们须要它支持中文字符，则将它的编码设置为utf8格式：orm

mysql> ALTER DATABASE testDB CHARACTER SET UTF8;
Query OK, 1 row affected (0.00 sec)

1.四、use使用数据库htm

mysql> use firstDB;
Database changed

1.五、查看当前使用的数据库blog

mysql> select database();
+------------+
| database() |
+------------+
| firstdb    |
+------------+
1 row in set (0.00 sec)

1.六、drop删除数据库排序

mysql> drop database firstDB;
Query OK, 0 rows affected (0.00 sec)

二、数据表（table）管理

咱们首先建立一个数据库，提供咱们日后的使用：

mysql> create database testDB;
Query OK, 1 row affected (0.00 sec)

建立后记得用use命令进入（使用）数据库，否则后面的操做都会不成功的。

2.一、create建立表

mysql> create table PEOPLE (
    -> ID int AUTO_INCREMENT PRIMARY KEY,
    -> NAME varchar(20) not null,
    -> AGE int not null,
    -> BIRTHDAY datetime);                                                     
Query OK, 0 rows affected (0.01 sec)

2.二、show显示表

显示当前数据库全部的数据表

mysql> show tables;
+------------------+
| Tables_in_testdb |
+------------------+
| PEOPLE           |
+------------------+
1 row in set (0.00 sec)

2.三、desc查看表结构

mysql> desc PEOPLE
    -> ;
+----------+-------------+------+-----+---------+----------------+
| Field    | Type        | Null | Key | Default | Extra          |
+----------+-------------+------+-----+---------+----------------+
| ID       | int(11)     | NO   | PRI | NULL    | auto_increment |
| NAME     | varchar(20) | NO   |     | NULL    |                |
| AGE      | int(11)     | NO   |     | NULL    |                |
| BIRTHDAY | datetime    | YES  |     | NULL    |                |
+----------+-------------+------+-----+---------+----------------+
4 rows in set (0.01 sec)

2.四、alter修改表结构（增、删、改）

默认建立的表不支持中文字符，因此需将表编码设置为utf8：

mysql> ALTER TABLE KEYCHAIN CONVERT TO CHARACTER SET UTF8;
Query OK, 1 row affected (0.02 sec)
Records: 1  Duplicates: 0  Warnings: 0

2.4.一、insert在表中添加列（字段）

mysql> alter table PEOPLE add star BOOL;
Query OK, 0 rows affected (0.02 sec)
Records: 0  Duplicates: 0  Warnings: 0

提示：在MySQL里，布尔类型会自动转换为tinyint(1)类型。

咱们不妨使用desc去查看一下PEOPLE表结构：

mysql> desc PEOPLE;
+----------+-------------+------+-----+---------+----------------+
| Field    | Type        | Null | Key | Default | Extra          |
+----------+-------------+------+-----+---------+----------------+
| ID       | int(11)     | NO   | PRI | NULL    | auto_increment |
| NAME     | varchar(20) | NO   |     | NULL    |                |
| AGE      | int(11)     | NO   |     | NULL    |                |
| BIRTHDAY | datetime    | YES  |     | NULL    |                |
| star     | tinyint(1)  | YES  |     | NULL    |                |
+----------+-------------+------+-----+---------+----------------+
5 rows in set (0.00 sec)

2.4.二、alter修改表（列）字段

mysql> alter table PEOPLE MODIFY star int;
Query OK, 0 rows affected (0.01 sec)
Records: 0  Duplicates: 0  Warnings: 0

也能够指定int(n)的长度，好比int(2)。

咱们再次使用desc查看PEOPLE表结构：

mysql> desc PEOPLE;
+----------+-------------+------+-----+---------+----------------+
| Field    | Type        | Null | Key | Default | Extra          |
+----------+-------------+------+-----+---------+----------------+
| ID       | int(11)     | NO   | PRI | NULL    | auto_increment |
| NAME     | varchar(20) | NO   |     | NULL    |                |
| AGE      | int(11)     | NO   |     | NULL    |                |
| BIRTHDAY | datetime    | YES  |     | NULL    |                |
| star     | int(11)     | YES  |     | NULL    |                |
+----------+-------------+------+-----+---------+----------------+
5 rows in set (0.00 sec)

2.4.三、delete删除表（列）字段

mysql> alter table PEOPLE DROP column star;
Query OK, 0 rows affected (0.02 sec)
Records: 0  Duplicates: 0  Warnings: 0

删除后，再次查看PEOPLE表结构：

mysql> desc PEOPLE;
+----------+-------------+------+-----+---------+----------------+
| Field    | Type        | Null | Key | Default | Extra          |
+----------+-------------+------+-----+---------+----------------+
| ID       | int(11)     | NO   | PRI | NULL    | auto_increment |
| NAME     | varchar(20) | NO   |     | NULL    |                |
| AGE      | int(11)     | NO   |     | NULL    |                |
| BIRTHDAY | datetime    | YES  |     | NULL    |                |
+----------+-------------+------+-----+---------+----------------+
4 rows in set (0.00 sec)

删除字段成功，如今咱们已经不能看到star的字段了。

2.4.四、rename重命名表名

mysql> RENAME TABLE PEOPLE TO NEW_PEOPLE;
Query OK, 0 rows affected (0.00 sec)

2.4.五、null or not null

修改表字段容许为空或不容许为空：

mysql> ALTER TABLE PEOPLE MODIFY AGE INT(3) NULL;
Query OK, 0 rows affected (0.01 sec)
Records: 0  Duplicates: 0  Warnings: 0

把PEOPLE表的AGE字段设置成“容许为空”，即插入记录时这个字段能够不录入。不然相反。

它的格式为：ALTER TABLE <TALBE_NAME> MODIFY <CLOUMN> <NULL 'OR' NOT NULL>

2.五、create利用已有数据建立新表

mysql> create table newTable select * from PEOPLE;
Query OK, 0 rows affected (0.01 sec)
Records: 0  Duplicates: 0  Warnings: 0

咱们查看一下目前数据库存在的表：

mysql> show tables;
+------------------+
| Tables_in_testdb |
+------------------+
| PEOPLE           |
| newTable         |
+------------------+
2 rows in set (0.00 sec)

三、数据的操做及管理

数据表的基本操做，包含增、删、改、查数据。

如下命令均在PEOPLE表上操做。

3.一、增长数据（增）

PEOPLE表目前是没有数据的，它是空的数据表，咱们如今先添加一些数据。

insert into命令添加数据：

mysql> insert into PEOPLE VALUES (null, 'Anny', 22, '1992-05-22');
Query OK, 1 row affected (0.00 sec)

使用select命令查看表（会在后面介绍），如今咱们查看PEOPLE数据表的数据：

mysql> select * from PEOPLE;
+----+------+-----+---------------------+
| ID | NAME | AGE | BIRTHDAY            |
+----+------+-----+---------------------+
|  1 | Anny |  22 | 1992-05-22 00:00:00 |
+----+------+-----+---------------------+
1 row in set (0.00 sec)

数据表如今有一条数据。

咱们多添加几条数据，如：

mysql> select * from PEOPLE;
+----+--------+-----+---------------------+
| ID | NAME   | AGE | BIRTHDAY            |
+----+--------+-----+---------------------+
|  1 | Anny   |  22 | 1992-05-22 00:00:00 |
|  2 | Garvey |  23 | 1991-05-22 00:00:00 |
|  3 | Lisa   |  25 | 1989-05-22 00:00:00 |
|  4 | Nick   |  24 | 1990-05-22 00:00:00 |
|  5 | Rick   |  24 | 1991-05-22 00:00:00 |
+----+--------+-----+---------------------+
5 rows in set (0.00 sec)

3.二、删除数据（删）

delete命令删除数据：

mysql> delete from PEOPLE where name = 'Lisa';
Query OK, 1 row affected (0.01 sec)

再次查询PEOPLE表：

mysql> select * from PEOPLE;
+----+--------+-----+---------------------+
| ID | NAME   | AGE | BIRTHDAY            |
+----+--------+-----+---------------------+
|  1 | Anny   |  22 | 1992-05-22 00:00:00 |
|  2 | Garvey |  23 | 1991-05-22 00:00:00 |
|  4 | Nick   |  24 | 1990-05-22 00:00:00 |
|  5 | Rick   |  24 | 1991-05-22 00:00:00 |
+----+--------+-----+---------------------+
4 rows in set (0.00 sec)

已经看不到名为“Lisa”的数据了。

3.三、修改数据（改）

update命令修改数据：

mysql> update PEOPLE set name='Calvin' where name = 'Garvey';
Query OK, 1 row affected (0.00 sec)
Rows matched: 1  Changed: 1  Warnings: 0

查询PEOPLE表内容：

mysql> select * from PEOPLE;
+----+--------+-----+---------------------+
| ID | NAME   | AGE | BIRTHDAY            |
+----+--------+-----+---------------------+
|  1 | Anny   |  22 | 1992-05-22 00:00:00 |
|  2 | Calvin |  23 | 1991-05-22 00:00:00 |
|  4 | Nick   |  24 | 1990-05-22 00:00:00 |
|  5 | Rick   |  24 | 1991-05-22 00:00:00 |
+----+--------+-----+---------------------+
4 rows in set (0.00 sec)

名为“Garvey”的记录已经修改成“Calvin”。

3.4 查询数据（查）

select命令查询数据，最简单的就是查询表的全部数据，也就是咱们最初使用到的那条命令：

mysql> select * from PEOPLE;
+----+--------+-----+---------------------+
| ID | NAME   | AGE | BIRTHDAY            |
+----+--------+-----+---------------------+
|  1 | Anny   |  22 | 1992-05-22 00:00:00 |
|  2 | Calvin |  23 | 1991-05-22 00:00:00 |
|  4 | Nick   |  24 | 1990-05-22 00:00:00 |
|  5 | Rick   |  24 | 1991-05-22 00:00:00 |
+----+--------+-----+---------------------+
4 rows in set (0.00 sec)

格式：select * from <表名>，*表明全部字段。

查询数据时也可指定显示的（列）字段：

mysql> select NAME, AGE, BIRTHDAY from PEOPLE;
+--------+-----+---------------------+
| NAME   | AGE | BIRTHDAY            |
+--------+-----+---------------------+
| Anny   |  22 | 1992-05-22 00:00:00 |
| Calvin |  23 | 1991-05-22 00:00:00 |
| Nick   |  24 | 1990-05-22 00:00:00 |
| Rick   |  24 | 1991-05-22 00:00:00 |
+--------+-----+---------------------+
4 rows in set (0.00 sec)

格式：select <字段名,字段名,...> from <表名>。

select查询命令还有不少的高级用法，好比用来查找不重复（distinct）的数据，使数据按条件排序（order by），按查询条件显示数据（where）等等。这些都会在下一篇文章做重点介绍，请你们继续留意个人博客，谢谢。

四、管理视图

建立视图

视图是从数据库里导出一个或多个表的虚拟表，是用来方便用户对数据的操做。

mysql> CREATE VIEW PEOPLE_VIEW (
    -> NAME, AGE)
    -> AS SELECT NAME, AGE FROM PEOPLE;

建立成功后查看视图。

PEOPLE          PEOPLE.AGE      PEOPLE.BIRTHDAY PEOPLE.ID       PEOPLE.NAME    
mysql> SELECT * FROM PEOPLE_VIEW
    -> ;
+--------+-----+
| NAME   | AGE |
+--------+-----+
| Anny   |  22 |
| Calvin |  23 |
| Nick   |  24 |
| Rick   |  24 |
+--------+-----+
4 rows in set (0.00 sec)

咱们也可使用DESC命令查看视图的结构。

mysql> DESC PEOPLE_VIEW;
+-------+---------+------+-----+---------+-------+
| Field | Type    | Null | Key | Default | Extra |
+-------+---------+------+-----+---------+-------+
| ID    | int(11) | NO   |     | 0       |       |
+-------+---------+------+-----+---------+-------+
1 row in set (0.01 sec)

替换视图

建立或替换原有视图。

mysql> CREATE OR REPLACE VIEW PEOPLE_VIEW(PEOPLE_ID,PEOPLE_NAME,PEOPLE_AGE) AS SELECT ID,NAME,AGE FROM PEOPLE;
Query OK, 0 rows affected (0.00 sec)

建立或替换后查看视图。

mysql> SELECT * FROM PEOPLE_VIEW;
+-----------+-------------+------------+
| PEOPLE_ID | PEOPLE_NAME | PEOPLE_AGE |
+-----------+-------------+------------+
|         1 | Anny        |         22 |
|         2 | Calvin      |         23 |
|         4 | Nick        |         24 |
|         5 | Rick        |         24 |
+-----------+-------------+------------+
4 rows in set (0.00 sec)

操做视图

当视图数据有变化时（增、删、改），真实的表数据也会随着改变。也就是说，对视图的操做就是对表的数据，因此咱们能够把视图看成表。

例：往视图插入一条数据。

mysql> INSERT INTO PEOPLE_VIEW VALUES(NULL, 'Kerry', '33');
Query OK, 1 row affected (0.00 sec)

插入数据成功后查看视图。

mysql> SELECT * FROM PEOPLE_VIEW ;
+-----------+-------------+------------+
| PEOPLE_ID | PEOPLE_NAME | PEOPLE_AGE |
+-----------+-------------+------------+
|         1 | Anny        |         22 |
|         2 | Calvin      |         23 |
|         4 | Nick        |         24 |
|         5 | Rick        |         24 |
|         6 | Kerry       |         33 |
+-----------+-------------+------------+
5 rows in set (0.00 sec)

能够在视图上看到咱们刚刚插入的数据，如今咱们就来验证一下真实的表是否也会做出变化。

mysql> SELECT * FROM PEOPLE;
+----+--------+-----+---------------------+
| ID | NAME   | AGE | BIRTHDAY            |
+----+--------+-----+---------------------+
|  1 | Anny   |  22 | 1992-05-22 00:00:00 |
|  2 | Calvin |  23 | 1991-05-22 00:00:00 |
|  4 | Nick   |  24 | 1990-05-22 00:00:00 |
|  5 | Rick   |  24 | 1991-05-22 00:00:00 |
|  6 | Kerry  |  33 | NULL                |
+----+--------+-----+---------------------+
5 rows in set (0.00 sec)

可见，真实的表数据也已经有所改变，刚刚往视图里插入的那一条数据存在于真实表中，真理即是：对视图的操做就是对表的数据。

删除视图

mysql> DROP VIEW PEOPLE_VIEW;
Query OK, 0 rows affected (0.00 sec)

参考：

http://www.cnblogs.com/GarveyCalvin/p/4297282.html