数据库插入，查询，删除

插入数据

insert into table_name (column_list) values(value_list)
插入一条记录

insert into person (id,name,age,info) values(1,'Green',21,'Lawyer');

列表名可以省略
例如：

insert into persion values(2,'Marry',24,'Musiacan');

可以插入指定列：

insert into person(name,age,info) values('Willam',20,'sports man');

同时插入多条记录

insert into persion(name,age,info) values('Evans',27,'secretary'),('Dale',22,'cok'),('Edision',28,'singer');

同时插入多条记录也可以省略字段名
将查询结果插入表中
insert into table_name (column_list) select (column_list2) from table_name2 where (condition)
需要插入的列表和查询表的类型要相同，对应的字段数据类型也要相同。
例如：
创建persion表

mysql> create table persion(
id INT unsigned not null auto_increment,
name varchar(11) not null,
position varchar(20),PRIMA
RY KEY(id));

插入数值

mysql> insert into persion(id,name,position)
values(2,'lihairu','student'),
(3,'liuboqin','teacher'),
(4,'wuguang','stude
t');

创建和表类型相同的表persion_old,并插入数值

mysql> insert into persion_old values
(8,'liuxun','student'),
(9,'wangyi','teacher'),
(10,'qixuan','moniter');

查询表persion_old的数据并插入到persion

insert into persion(id,name,position) select id ,name,position from persion_old;

结果就是将persion_old的三条记录插入到了表persion

mysql> select * from persion;
+----+-----------+------------+
| id | name      | position   |
+----+-----------+------------+
|  1 | 18        | musication |
|  2 | lihairu   | student    |
|  3 | liuboqin  | teacher    |
|  4 | wuguang   | student    |
|  6 | zhangqian | student    |
|  7 | wangchong | student    |
|  8 | liuxun    | student    |
|  9 | wangyi    | teacher    |
| 10 | qixuan    | moniter    |
+----+-----------+------------+

更新数据
update table_name set column_name1=value1,column_name2=value2,......,columnn=valuen where (condition);
例如，为persion添加age字段，并更新数据为19-24，修改id=1的name值为‘wanghai’.
用alter语句添加字段

 alter table persion add age INT(4) not null after id;

更新年龄值为19-24

 update persion set age=(floor(rand()*6)+19);

查看效果：

mysql> select * from persion;
+----+-----+-----------+------------+
| id | age | name      | position   |
+----+-----+-----------+------------+
|  1 |  19 | 18        | musication |
|  2 |  22 | lihairu   | student    |
|  3 |  23 | liuboqin  | teacher    |
|  4 |  19 | wuguang   | student    |
|  6 |  19 | zhangqian | student    |
|  7 |  20 | wangchong | student    |
|  8 |  19 | liuxun    | student    |
|  9 |  22 | wangyi    | teacher    |
| 10 |  21 | qixuan    | moniter    |
+----+-----+-----------+------------+

看到id=1的不协调的name字段为18，改为’wanghai’

update persion set name='wanghai' where id=1;

查看结果：

mysql> select name from persion where id=1;
+---------+
| name    |
+---------+
| wanghai |
+---------+

如果不用where条件语句，数据库将默认为将该字段所有的值改为要修改的值

删除数据
delete from table_name [where <condition>];
例如：

delete from persion where id=10;

也可以用范围语句

delete from persion where age between 19 and 21;

在不添加条件时，表示清空表中内容。
删除表中所有数据还可以用truncate
truncate table_name
truncate 的原理并不是清除表的数据，而是直接删除表，然后重新创建新的。