sql数据库基本语句

一、创建表

1.创建表 

CREATE TABLE cre_uer (
id INT(10) NOT NULL PRIMARY KEY,
maner VARCHAR(20) ,
sex VARCHAR(10),
age INT(4),
city VARCHAR(30),
worker VARCHAR(40),
marker INT(10));  // cre_uer是表名

2.复制表

create table copyuser select * from cre_user;   (创建一张和cre_uer一样的表)  //copyuser是表名

二、删除表

drop table copyuser；//copyuser是表名

三、插入表

1.插入表

insert into cre_uer （id，maner,sex,age,city,worker,marker）values(1,'张三','女',23,'杭州','会计',9)

2.插入查询出来的输入

insert into cre_uer（id，maner,sex,age）select id,maner,sex,age from cre_uer;

四、查询语句

1.查询整张表

select * from cre_uer;

2.排序查询

select * from cre_uer order by id decs;//id倒序排列      acs正序排列

3.查询marker的和

select sum(marker) as summarker from cre_uer;

4.查询marker平均值

select avg（marker）as avgmarker from cre_uer;

5.查询最大值

select max（marker） maxmarker form cre_uer;

6.查询最小值

select min（marker）minmarker from cre_uer;

五、删除表数据

delete from test_management.`cre_uer` where marker  is null;  //删除cre_uer表中marker为null的的数据
delete from test_management.`cre_uer` where city='洛阳'  //删除cre_uer表中 city为洛阳的数据