MySQL有很多的可視化管理工具,比如“mysql-workbench”和“sequel-pro-”。 現(xiàn)在我寫MySQL的終端命令操作的文章,是想強化一下自己對于MySQL的理解,總會比使用圖形化的理解透徹,因為我本來就比較喜歡寫代碼。同時寫出來這些文章,是想要給大家當個參考,希望也能對大家有所幫助,有所提升,這就是我為什么要寫終端操作MySQL的文章了。

注意:MySQL數(shù)據(jù)庫命令不區(qū)分大小寫。但在MAC的終端,如果你想使用tab自動補全命令,那么你就必須使用大寫,這樣MAC的終端才會幫你補全命令,否則你按N遍tab都不會有響應(yīng)。

1、數(shù)據(jù)庫(database)管理

1.1 create 創(chuàng)建數(shù)據(jù)庫

create database firstDB;

1.2 show 查看所有數(shù)據(jù)庫

mysql> show databases;

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

1.3 alter 修改數(shù)據(jù)庫

alter 命令修改數(shù)據(jù)庫編碼:

默認創(chuàng)建的數(shù)據(jù)庫默認不支持中文字符,如果我們需要它支持中文字符,則將它的編碼設(shè)置為utf8格式:

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

1.4 use 使用數(shù)據(jù)庫

mysql> use firstDB;
Database changed

1.5 查看當前使用的數(shù)據(jù)庫

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

1.6 drop 刪除數(shù)據(jù)庫

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

2、數(shù)據(jù)表(table)管理

我們首先創(chuàng)建一個數(shù)據(jù)庫,提供我們往后的使用:

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

創(chuàng)建后記得用use命令進入(使用)數(shù)據(jù)庫,不然后面的操作都會不成功的。

2.1 create 創(chuàng)建表

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)

2.2 show 顯示表

顯示當前數(shù)據(jù)庫所有的數(shù)據(jù)表

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

2.3 desc 查看表結(jié)構(gòu)

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)

2.4 alter 修改表結(jié)構(gòu)(增、刪、改)

默認創(chuàng)建的表不支持中文字符,所以需將表編碼設(shè)置為utf8:

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

2.4.1 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,布爾類型會自動轉(zhuǎn)換為tinyint(1)類型。

我們不妨使用desc去查看一下PEOPLE表結(jié)構(gòu):

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)

現(xiàn)在,你該相信我了吧?

2.4.2 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

我們再次使用desc查看PEOPLE表結(jié)構(gòu):

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)

2.4.3 delete 刪除表(列)字段

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

刪除后,再次查看PEOPLE表結(jié)構(gòu):

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)

刪除字段成功,現(xiàn)在我們已經(jīng)不能看到star的字段了。

2.4.4 rename 重命名表名

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

2.5 create 利用已有數(shù)據(jù)創(chuàng)建新表

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

我們查看一下目前數(shù)據(jù)庫存在的表:

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

3、數(shù)據(jù)的操作及管理

數(shù)據(jù)表的基本操作,包含增、刪、改、查數(shù)據(jù)。

以下命令均在PEOPLE表上操作。

3.1 增加數(shù)據(jù)(增)

PEOPLE表目前是沒有數(shù)據(jù)的,它是空的數(shù)據(jù)表,我們現(xiàn)在先添加一些數(shù)據(jù)。

insert into 命令添加數(shù)據(jù):

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(會在后面介紹),現(xiàn)在我們查看PEOPLE數(shù)據(jù)表的數(shù)據(jù):

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

數(shù)據(jù)表現(xiàn)在有一條數(shù)據(jù)。

我們多添加幾條數(shù)據(jù),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)

3.2 刪除數(shù)據(jù)(刪)

delete 命令刪除數(shù)據(jù):

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

再次查詢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)

已經(jīng)看不到名為“Lisa”的數(shù)據(jù)了。

3.3 修改數(shù)據(jù)(改)

update 命令修改數(shù)據(jù):

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

查詢PEOPLE表內(nèi)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)

名為“Garvey”的記錄已經(jīng)修改為“Calvin”。

3.4 查詢數(shù)據(jù)(查)

select 命令查詢數(shù)據(jù),最簡單的就是查詢表的所有數(shù)據(jù),也就是我們最初使用到的那條命令:

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>,*代表所有字段。

查詢數(shù)據(jù)時也可指定顯示的(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查詢命令還有很多的高級用法,比如用來查找不重復(fù)(distinct)的數(shù)據(jù),使數(shù)據(jù)按條件排序(order by),按查詢條件顯示數(shù)據(jù)(where)等等。這些都會在下一篇文章作重點介紹,請大家繼續(xù)留意我的博客,謝謝。

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