mysql字符集，insert,update,delete,select

xiaoxiao2023-07-31 122

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\charsets\ |+--------------------------+----------------------------------------------------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femaleupdate 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.sqlcreate 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;