mysql中一些常用的命令

1.SQL简介：Structured Query Language结构化查询语言

DQL:数据查询语言

DCL:数据控制语言

DML:数据操作语言

TPL :事物处理语言

DDL:数据定义语言

CCL:事物控制语言

2.数据定义语言

create database mysql1 character set gbk;本地编码

create database mysql1 character set gbk collate gbk_chinese_ci;带校对

drop databases 数据库名；删除数据库

alter table 表名 add image blob;增加表中的列

alter tabla 表名 modify job varchar(10);修改字符长度

alter table 表名 drop image;删除表

rename table 表名 to user;改表名字

alter table 表名 character set utf8;修改字符集utf8

3.简单查询语言

select * form; 查询所有的信息

select name, age from 表名;查询个别的信息

select distinct english from student;过滤表中重复的数据

where查询

<1>.select name chinese math english from student where name="";

<2>.select name chinese math english from student where english>90;

<3>.select * from student where(chinese+math+english)>200;

<4>where查询支持运算表达式

1.select * from student where english between 80 and 90

2.select * from student where math in(89,90,91);

3.select * from student where name like '李%';

4.select * from student where math>90 and chinese>80;

<5>order查询

1.select * from student order by math;

2.select * from student order by (++) desc;

3.select name math from student where name like '李%';

4.数据操作语言

update user set salary=500;

update user set salary=300 where name="";

delete from user where name="";

delete from user;

使用truncate删除整张表中的记录

truncate user;(摧毁整张表，重建整张表)