1.增加内容
insert into info valuse ('poo1','张三',1,'n001','1989-2-3')
insert into info（code,name列名）valuse('p002','李四') 必包含主键
2.删除数据
delete from info 删除表
delete from info where code='p002'
3.修改数据
update info set name='李四' 全部修改为李四
update info set name='李四' where code='p001'
4.查询数据
（1）简单查询
select * from info 查询所有内容 *代表所有列
select code,name from info 查询指定列
select code as '代号',name as '姓名' from info 查询指定列且替换了列名
（2）条件查询
select * from car where code='c002' 单条件
select * from car where trun 查询所有内容
select * from car where brand='b001'and pawers='130' 多条件查询 and并且关系
select * from car where brand='b001'or pawers='130' or或者关系
(3)模糊查询
select * from car where name like'%奥迪%' %代表任意多个字符 _代表一个任意的字符
（4）排序查询
select * from car order by powers asc/desc 单列排序 asc升序desce降序 默认升序，可不写asc
select * from car order by brand asc,powers desc asc可不写 双列排序
（5）范围查询
select * from car where price>=40 and price<=60 60>=价格>=40
select * from car where price between 40 and 60 60>=价格>=40
(6）离散查询
select * from car where code in ('c001','c003','c005','c007') 用来查找code里的('c001','c003','c005','c007') 如果寻找非，用not in
(7）聚合函数，统计查询
select sum(price) from car 查询car中所有价格之和 sum()求和 不可用于字符串
select count(*) from car 查询car中所有数据条数 *可替换为列名 可用于字符串
select max(price) from car 查询列最大值 可用于字符串
select min(price) from car 查询列最小值 可用于字符串 字符串null最小
select avg(price) from car 查询平均值 不可用于字符串
（8）分页查询
每页显示x条数据，现在取第n页的数据
select * from limit (n-1)*x,取多少
（9）去重查询
select distinct brand from car 去掉brand列的重复
（10）分组查询
select count(*),bround from car group by brand 分组查数量
select brand from car group by brand having count(*)>3 分组之后根据条件查询使用having，不能用where