show databases;

drop database shujuku_name;/*删除*/
create database shujuku_name;/*创建数据库*/
use shujuku_name;

show tables;
drop table biao_name;
create table biao_name{
ziduan0 int,
ziduan1 varchar(20),
ziduan2 int(5)
};
desc biao_name;/*查看表结构*/
alter table biao_name add colum ziduan_name varchar(10);/*添加字段*/
/*添加删除修改字段时colum可以省略 如下*/
alter table biao_name drop colum ziduan_name;/*删除字段*/
/*adds是添加 drop是删除 modify是修改类型*/
alter table biao_name change zifuan_name ziduan_new_name varchar(20);
alter table biao_name change zifuan_new_name ziduan_name varchar(10);
alter table biao_name rename to table_name;/*修改表名*/

/*增删改查*/
insert into table_name values(1,'字段1',666);
insert into table_name(ziduan1,ziduan2) values('字段2',999)
delete from table_name where ziduan2='字段2';
delete from table_name where ziduan2='字段2' and ziduan1='字段1';
/*不添加where这个条件时整个表全部的内容都删除*/
update table_name set ziduan0=123,diduan1='字段one' where ziduan1='字段1' ziduan2=666;
select * from table_name;
select ziduan1,ziduan2 as '字段二' from table_name;/*查询时添加常量列别名*/