MariaDB 插入&更新&删除数据(8)

MariaDB数据库管理系统是MySQL的一个分支,主要由开源社区在维护,采用GPL授权许可MariaDB的目的是完全兼容MySQL,包括API和命令行,MySQL由于现在闭源了,而能轻松成为MySQL的代替品.在存储引擎方面,使用XtraDB来代替MySQL的InnoDB,MariaDB由MySQL的创始人Michael Widenius主导开发,他早前曾以10亿美元的价格,将自己创建的公司MySQL AB卖给了SUN,此后,随着SUN被甲骨文收购MySQL的所有权也落入Oracle的手中.MariaDB名称来自MichaelWidenius的女儿Maria的名字.

存储在系统中的数据是数据库管理系统(DBMS)的核心,数据库被设计用来管理数据的存储、访问和维护数据的完整性,MariaDB中提供了功能丰富的数据库管理语句,包括有效地向数据库中插入数据的INSERT语句,更新数据的UPDATE语句以及当数据不再使用时删除数据的DELETE语句,本小结将依次来介绍这些命令的使用方法和技巧.

MariaDB 插入数据

MariaDB中使用INSERT语句插入数据,可以插入的方式有:插入完整记录,插入记录的部分,插入多条记录,插入另一个查询的结果,废话不多说,老样子先来看一下插入语句的写法吧:

INSERT INTO 表名称(字段1,字段2,字段3,.....) VALUES(数值1,数值2,数值3....)

为了方便后续的练习,我们先来创建一个表结构,SQL语句如下:

MariaDB [lyshark]> create table person
    -> (
    -> id int unsigned not null auto_increment,
    -> name char(50) not null default '',
    -> age int not null default 0,
    -> info char(50) null,
    -> primary key(id)
    -> );
Query OK, 0 rows affected (0.00 sec)

◆在所有字段插入数据◆

在person表中,插入一条新记录id=1,name=LyShark,age=22,info=Lawyer,SQL语句如下:

MariaDB [lyshark]> select * from person;
Empty set (0.00 sec)
 
MariaDB [lyshark]> insert into person(id,name,age,info) values(1,'LyShark',22,'Lawyer');
Query OK, 1 row affected (0.00 sec)
 
MariaDB [lyshark]> select * from person;
+----+---------+-----+--------+
| id | name    | age | info   |
+----+---------+-----+--------+
|  1 | LyShark |  22 | Lawyer |
+----+---------+-----+--------+
1 row in set (0.00 sec)
 
MariaDB [lyshark]>

◆在指定字段插入数据◆

在person表中,插入一条新记录,name=Willam,age=18,info=sports,我们不给其指定ID,SQL语句如下:

MariaDB [lyshark]> desc person;
+-------+------------------+------+-----+---------+----------------+
| Field | Type             | Null | Key | Default | Extra          |
+-------+------------------+------+-----+---------+----------------+
| id    | int(10) unsigned | NO   | PRI | NULL    | auto_increment |
| name  | char(50)         | NO   |     |         |                |
| age   | int(11)          | NO   |     | 0       |                |
| info  | char(50)         | YES  |     | NULL    |                |
+-------+------------------+------+-----+---------+----------------+
4 rows in set (0.00 sec)
 
MariaDB [lyshark]> insert into person(name,age,info) values('Willam',18,'sports man');
Query OK, 1 row affected (0.04 sec)
 
MariaDB [lyshark]> select * from person;
+----+---------+-----+------------+
| id | name    | age | info       |
+----+---------+-----+------------+
|  1 | LyShark |  22 | Lawyer     |
|  2 | Willam  |  18 | sports man |
+----+---------+-----+------------+
2 rows in set (0.00 sec)
 
MariaDB [lyshark]>

◆同时为表插入多条记录◆

在person表中,同时插入3条新记录,有多条只需要在每一条的后面加,即可,SQL语句如下:

MariaDB [lyshark]> select * from person;
+----+---------+-----+------------+
| id | name    | age | info       |
+----+---------+-----+------------+
|  1 | LyShark |  22 | Lawyer     |
|  2 | Willam  |  18 | sports man |
+----+---------+-----+------------+
2 rows in set (0.00 sec)
 
MariaDB [lyshark]> insert into person(name,age,info) values('Evans',27,'secretary'),
    -> ('Dale',22,'cook'),
    -> ('Edison',28,'singer');
Query OK, 3 rows affected (0.01 sec)
Records: 3  Duplicates: 0  Warnings: 0
 
MariaDB [lyshark]> select * from person;
+----+---------+-----+------------+
| id | name    | age | info       |
+----+---------+-----+------------+
|  1 | LyShark |  22 | Lawyer     |
|  2 | Willam  |  18 | sports man |
|  3 | Evans   |  27 | secretary  |
|  4 | Dale    |  22 | cook       |
|  5 | Edison  |  28 | singer     |
+----+---------+-----+------------+
5 rows in set (0.00 sec)

◆将查询结果插入到表中◆

为了实现将另一个表中的记录插入到本表中,我们新建一个person_old表,其表结构和person相同,我们将person_old表中的内容全部迁移到person中去,SQL语句如下:

1.创建一个person_old表,并插入测试字段:

MariaDB [lyshark]> create table person_old
    -> (
    -> id int unsigned not null auto_increment,
    -> name char(50) not null default '',
    -> age int not null default 0,
    -> info char(50) null,
    -> primary key(id)
    -> );
Query OK, 0 rows affected (0.01 sec)
 

MariaDB [lyshark]> insert into person_old
    -> values(11,'harry',20,'student'),(12,'Beckham',33,'police');
Query OK, 2 rows affected (0.00 sec)
Records: 2  Duplicates: 0  Warnings: 0

2.接下来我们将person_old表中的内容迁移到person中去

MariaDB [lyshark]> select * from person_old;
+----+---------+-----+---------+
| id | name    | age | info    |
+----+---------+-----+---------+
| 11 | harry   |  20 | student |
| 12 | Beckham |  33 | police  |
+----+---------+-----+---------+
2 rows in set (0.00 sec)

MariaDB [lyshark]> select * from person;
+----+---------+-----+------------+
| id | name    | age | info       |
+----+---------+-----+------------+
|  1 | LyShark |  22 | Lawyer     |
|  2 | Willam  |  18 | sports man |
|  3 | Evans   |  27 | secretary  |
|  4 | Dale    |  22 | cook       |
|  5 | Edison  |  28 | singer     |
+----+---------+-----+------------+
5 rows in set (0.00 sec)
 

MariaDB [lyshark]> insert into person(id,name,age,info)
    -> select id,name,age,info from person_old;

Query OK, 2 rows affected (0.00 sec)
Records: 2  Duplicates: 0  Warnings: 0
 
MariaDB [lyshark]> select * from person;
+----+---------+-----+------------+
| id | name    | age | info       |
+----+---------+-----+------------+
|  1 | LyShark |  22 | Lawyer     |
|  2 | Willam  |  18 | sports man |
|  3 | Evans   |  27 | secretary  |
|  4 | Dale    |  22 | cook       |
|  5 | Edison  |  28 | singer     |
| 11 | harry   |  20 | student    |
| 12 | Beckham |  33 | police     |
+----+---------+-----+------------+
7 rows in set (0.00 sec)

MariaDB 更新数据

表中有数据之后,接下来我们可以对数据进行更新操作,MariaDB中使用UPDATE语句更新表中的记录,可以更新特定的行或同时更新所有的行,基本语句结构如下:

UPDATE 表名称
SET 字段1=修改值,字段2=修改值,字段3=修改值
where (限定条件);

◆更新表中指定字段◆

修改person表中数据,将id=11的name字段的值改为xxxx,age字段改为200,SQL语句如下:

MariaDB [lyshark]> select * from person;
+----+---------+-----+------------+
| id | name    | age | info       |
+----+---------+-----+------------+
|  1 | LyShark |  22 | Lawyer     |
|  2 | Willam  |  18 | sports man |
|  3 | Evans   |  27 | secretary  |
|  4 | Dale    |  22 | cook       |
|  5 | Edison  |  28 | singer     |
| 11 | harry   |  20 | student    |
| 12 | Beckham |  33 | police     |
+----+---------+-----+------------+
7 rows in set (0.00 sec)
 
MariaDB [lyshark]> update person set age=200,name='xxxx' where id=11;  #更新单个字段
Query OK, 1 row affected (0.00 sec)
Rows matched: 1  Changed: 1  Warnings: 0
 
MariaDB [lyshark]> select * from person;
+----+---------+-----+------------+
| id | name    | age | info       |
+----+---------+-----+------------+
|  1 | LyShark |  22 | Lawyer     |
|  2 | Willam  |  18 | sports man |
|  3 | Evans   |  27 | secretary  |
|  4 | Dale    |  22 | cook       |
|  5 | Edison  |  28 | singer     |
| 11 | xxxx    | 200 | student    |
| 12 | Beckham |  33 | police     |
+----+---------+-----+------------+
7 rows in set (0.00 sec)

◆更新表的一个范围◆

更新person表中的记录,将1-12的info字段全部改为lyshark blog,SQL语句如下:

MariaDB [lyshark]> select * from person;
+----+---------+-----+------------+
| id | name    | age | info       |
+----+---------+-----+------------+
|  1 | LyShark |  22 | Lawyer     |
|  2 | Willam  |  18 | sports man |
|  3 | Evans   |  27 | secretary  |
|  4 | Dale    |  22 | cook       |
|  5 | Edison  |  28 | singer     |
| 11 | xxxx    | 200 | student    |
| 12 | Beckham |  33 | police     |
+----+---------+-----+------------+
7 rows in set (0.00 sec)
 
MariaDB [lyshark]> update person set info='lyshark blog' where age between 1 and 200;  #指定修改的字段
Query OK, 7 rows affected (0.00 sec)
Rows matched: 7  Changed: 7  Warnings: 0
 
MariaDB [lyshark]> select * from person;
+----+---------+-----+--------------+
| id | name    | age | info         |
+----+---------+-----+--------------+
|  1 | LyShark |  22 | lyshark blog |
|  2 | Willam  |  18 | lyshark blog |
|  3 | Evans   |  27 | lyshark blog |
|  4 | Dale    |  22 | lyshark blog |
|  5 | Edison  |  28 | lyshark blog |
| 11 | xxxx    | 200 | lyshark blog |
| 12 | Beckham |  33 | lyshark blog |
+----+---------+-----+--------------+
7 rows in set (0.00 sec)

MariaDB 删除数据

◆删除表中指定记录◆

通过id号,删除表中指定列,此处删除第id=12号,这条记录,SQL语句如下:

MariaDB [lyshark]> select * from person;
+----+---------+-----+--------------+
| id | name    | age | info         |
+----+---------+-----+--------------+
|  1 | LyShark |  22 | lyshark blog |
|  2 | Willam  |  18 | lyshark blog |
|  3 | Evans   |  27 | lyshark blog |
|  4 | Dale    |  22 | lyshark blog |
|  5 | Edison  |  28 | lyshark blog |
| 11 | xxxx    | 200 | lyshark blog |
| 12 | Beckham |  33 | lyshark blog |
+----+---------+-----+--------------+
7 rows in set (0.00 sec)
 
MariaDB [lyshark]> delete from person where id=12;   #通过id号，删除表中指定列
Query OK, 1 row affected (0.05 sec)
 
MariaDB [lyshark]> select * from person;
+----+---------+-----+--------------+
| id | name    | age | info         |
+----+---------+-----+--------------+
|  1 | LyShark |  22 | lyshark blog |
|  2 | Willam  |  18 | lyshark blog |
|  3 | Evans   |  27 | lyshark blog |
|  4 | Dale    |  22 | lyshark blog |
|  5 | Edison  |  28 | lyshark blog |
| 11 | xxxx    | 200 | lyshark blog |
+----+---------+-----+--------------+
6 rows in set (0.00 sec)

◆删除表的一个范围◆

在person表中,删除age字段值在19-22的记录,SQL语句如下:

MariaDB [lyshark]> select * from person;
+----+---------+-----+--------------+
| id | name    | age | info         |
+----+---------+-----+--------------+
|  1 | LyShark |  22 | lyshark blog |
|  2 | Willam  |  18 | lyshark blog |
|  3 | Evans   |  27 | lyshark blog |
|  4 | Dale    |  22 | lyshark blog |
|  5 | Edison  |  28 | lyshark blog |
| 11 | xxxx    | 200 | lyshark blog |
+----+---------+-----+--------------+
6 rows in set (0.00 sec)
 
MariaDB [lyshark]> delete from person where age between 19 and 22;    #指定范围删除
Query OK, 2 rows affected (0.00 sec)
 
MariaDB [lyshark]> select * from person;
+----+--------+-----+--------------+
| id | name   | age | info         |
+----+--------+-----+--------------+
|  2 | Willam |  18 | lyshark blog |
|  3 | Evans  |  27 | lyshark blog |
|  5 | Edison |  28 | lyshark blog |
| 11 | xxxx   | 200 | lyshark blog |
+----+--------+-----+--------------+
4 rows in set (0.00 sec)

◆清空表中所有记录◆

MariaDB [lyshark]> select * from person;
+----+--------+-----+--------------+
| id | name   | age | info         |
+----+--------+-----+--------------+
|  2 | Willam |  18 | lyshark blog |
|  3 | Evans  |  27 | lyshark blog |
|  5 | Edison |  28 | lyshark blog |
| 11 | xxxx   | 200 | lyshark blog |
+----+--------+-----+--------------+
4 rows in set (0.00 sec)
 
MariaDB [lyshark]> delete from person;   #清空表中所有记录
Query OK, 4 rows affected (0.00 sec)
 
MariaDB [lyshark]> select * from person;
Empty set (0.00 sec)