1.插入数据

insert  into  表名（列1，列2，列3）values（值1，值2，值3）;

insert  into product(name,price,pic_path) values(‘jack’,25,’updown’);

2.更新数据

update  表名 set 列名1=值1，列名2=值2  where 条件;

update product set name=”jack”,price=35 where id=2;

3.删除数据库

delete from 表名[where 条件]

delete from product where id=2;

4.查询所有数据库内容

select * from 表名;

select * from product;

5.查询部分列

select 列1，列2 from 表名;

select id,name from product;

6.条件查询

#比较 =，>,<,>=,<=,!=

select * from 表名 where列名=值;

select * from product where id=2;

#and与

select * from 表名 where 条件1 and 条件2 and 条件3;

select * from product where id=2 and name=’Nike’;

#or 或

select * from 表名 where 条件1 or 条件2 or 条件3；

select * from product where name=’Nike’ or id=2;

#not 非

select * from 表名 where not 条件1;

select * from product where not name=’Nike’;

#in枚举

select * from 表名where 列名 in(值1，值2，值3);

select * from product where  id in(2,3,4,10);

select * from product where id not in(2,3,4);

#like模糊查询

select * from 表名where列名 like ‘%值%’;

select * from product where name like ‘%LI%’;

#between….and  范围查询

select * from 表名 where 列名 between 值1 and 值2；

select * from product where created between ‘2010-10-10’ and ‘2011-10-10’;

#limit行数查询

select * from 表名 limit  n1,n2;（n1：从第几行开始，从0开始算；n2：要显示几行）

select * from product limit 3,4;

7.查询排序

select * from 表名 order by列表排序方式。

#排序方式:asc(升序），desc（降序）；

select * from product order by created desc;

8.聚合函数

#count 总记录数

select  count(列名) from student;

select count(id) from student;

#sum 总共

select  sum(列名） from student;

select sum(age) from student;

#avg  平均值

select avg（列名）from student;

select avg(age) from student;

#max  最大值

select max（列名）from student；

select max(age) from student;

#min  最小值

select  min(列名) from 表名;

select min(age) from student;

9.子查询

select name from student where age<(select avg(age) from student);

select * from product where id in(select id from order);