mysql字符集，insert,update,delete,select
发现有错误：数据太长了。
//查看数据库的所有编码：
show variables like 'character%';
-----+
| character_set_client | utf8 设置客户端的字符集
|
| character_set_connection | utf8 设置连接的字符集
|
| character_set_database | utf8 设置数据库的字符集
|
| character_set_filesystem | binary 设置文件系统的字符集
|
| character_set_results | utf8 设置显示结果是使用的编码
|
| character_set_server | utf8 设置配置MySQL时设置的字符集
|
| character_set_system | utf8
|
| character_sets_dir | C:\Program Files\MySQL\MySQL Server 5.0\share\chars
ets\ |
+--------------------------+----------------------------------------------------
解决乱码的问题：
1、设置客户端的结果集
2、设置显示结果的字符集
1,set character_set_client=gbk; 使用的客户端编码
2,set character_set_results=gbk; 结果集的编码
创建一张a表
create table a
(
id int,
name varchar(20)
);
insert into a values(1,'aaa');
insert into a values('bbbb');//只想添加name时，要把a(name)写上。
insert into a(name) values('bbbb');
+------+------+
| id | name |
+------+------+
| 1 | aaa |
| NULL | bbbb |
+------+------+
实际上into也可以不写。
insert a values(2,'cccc');
insert a values(3,'dddd');
上面的等价下面的：
insert a value(4,'cccc'),(5,'dddd');
select * from employee;
将所有的员工的薪水修改为5000元
update employee set salary=5000;
将姓名为 zhangsan 的员工的薪水修改为3000元
update employee set salary=3000 where name='zhangsan';
将姓名为 lisi 的员工薪水修改为4000元，sex修改为female
update employee set salary=4000,gender='female' where name='lisi';
将xiaohong的薪水在原有的基础上增加1000元。
update employee set salary=salary+1000 where name='xiaohong';
set character_set_results=gbk;
3delete语句 删除数据
删除表中name为zhangsan 的记录
delete from employee where name='zhangsan';
删除表中的所有数据
delete from employee;
insert into employee
(id,name,gender,birthday,salary,entry_date,resume)
values(1,'zhangsan','male','1980-1-1',1000,'2000-3-16','good boy');
insert into employee
(id,name,gender,birthday,salary,entry_date,resume)
values(2,'lisi','male','1934-4-1',1000,'2010-3-16','good boy');
insert into employee
(id,name,gender,birthday,salary,entry_date,resume)
values(3,'xiaohong','female','1984-1-1',1000,'2008-3-16','good girl');
使用truncate删除表中的记录
truncate employee; 删除表中的记录。删除表在创建表
select * from employee;
insert into employee
(id,name,gender,birthday,salary,entry_date,resume)
values(1,'zhangsan','male','1980-1-1',1000,'2000-3-16','good boy');
insert into employee
(id,name,gender,birthday,salary,entry_date,resume)
values(2,'lisi','male','1934-4-1',1000,'2010-3-16','good boy');
insert into employee
(id,name,gender,birthday,salary,entry_date,resume)
values(3,'xiaohong','female','1984-1-1',1000,'2008-3-16','good girl');
select * from employee;
mysql> select * from employee;
+------+----------+--------+------------+--------+------------+-----------+
| id | name | gender | birthday | salary | entry_date | resume |
+------+----------+--------+------------+--------+------------+-----------+
| 1 | zhangsan | male | 1980-01-01 | 1000 | 2000-03-16 | good boy |
| 2 | lisi | male | 1934-04-01 | 1000 | 2010-03-16 | good boy |
| 3 | xiaohong | female | 1984-01-01 | 1000 | 2008-03-16 | good girl |
+------+----------+--------+------------+--------+------------+-----------+
4、select 语句
column 指定列名
* 号代表查询所有列
From 指定查询哪张表
DISTINCT可选，值显示结果时，是否剔除重复数据。
student.sql
create table student
(
id int,
name varchar(20),
chinese float,
english float,
math float
);
insert into student(id,name,chinese,english,math) values(1,'张小明',89,78,90);
insert into student(id,name,chinese,english,math) values(2,'李菁',67,53,95);
insert into student(id,name,chinese,english,math) values(3,'王五',87,78,77);
insert into student(id,name,chinese,english,math) values(4,'李一',82,98,92);
insert into student(id,name,chinese,english,math) values(5,'李来才',82,84,67);
insert into student(id,name,chinese,english,math) values(6,'张警报',55,85,45);
insert into student(id,name,chinese,english,math) values(1,'黄蓉',75,65,30);
//查询所有的学生的信息
select * from student;
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