一、库
库即文件夹
增:create database db charset utf8;
查:show databases;
show create database db;
改:alter database db charset gbk;
删:drop database db;
二、文件夹
在对文件夹进行修改时需要选择对应的库
增:create table student(id int,name char); create table db.student(id int,name char); 查:show tables; show create table student; desc student; 改:alter table student add age int; alter table student modify name char(15); alter table student change name NAME char(10); # 删除表格中的某一个属性 alter table student drop age; 删:drop table student;
三、文件
增:insert into student(id,name) values (1,'dawang'), (2,'xiaoer'); 查:select * from student; select name from db.student; select id,name from student; select id from student where id=2; 改:update db.student set name='DAWANG' where id =1; 删:delete from student where id =1; truncate student; # delete 和 truncate的区别: # delete 删除表格中某一行时,会保留之前的id,即在之后创建的数据id 都会以之前的为起始 # truncate 清除整个表格,id号会清空,下次新增的id会重新开始计数