增删改查

#输出当前已有的数据库
show databases;
#如果数据库demo1不存在，则创建数据库demo1
create database if not exists demo1;
#选择使用数据库demo
use demo;
#删
delete from student where name = '周瑜';
#增
insert into student (id, name, sex, score) values ('1013', '周瑜', '男', '78');
#查
select * from student s where name = '曹操';
#改
update student set score = '100' where name = '诸葛亮';