MySQL学习-DML（Data Manipulation Language）数据

回顾DDL语言：

show databases;

create database hufei;

use hufei;

create table emp(name varchar(20),age int(10));

show create table emp \G;

alter table emp rename empp;

show create table empp \G;

alter table empp add column height int(10) first;

desc empp;

alter table empp drop column height;

desc empp;

alter table empp modify name varchar(10);

desc empp;

alter table empp change name newname varchar(20);

desc empp;

drop table empp;

 

DML 对数据库中表记录的操作，主要包括记录的插入（insert）、删除（delete）、改（update）、查（select）

create database hufei;

use hufei;

create table emp(

ename varchar(10),

hiredate date,sal

decimal(10,2),

deptno int(2)

);

create table dept(

deptno int(2),

deptname varchar(10)

);

增：insert

insert into emp values('zzx','2000-01-01','100',1),('lisa','2001-01-01','200',3);

insert into emp values('lifei','2020-01-01','300',2);

insert into emp values('yangfei','2011-01-01','2000',2);

insert into dept values(1,'tech');

insert into dept values(2,'sale');

insert into dept values(5,'fin');

select * from emp;

select * from dept;

删除：delete，不管是单表还是

delete from emp where ename='lifei';