重启mysql提示MySQL server PID file could not be found!
1. ps -ef|grep mysqld
2. kill -9 进程号
DML&DDL
数据操作语言DML
select
update
delete
insert into
数据定义语言DDL
crate database
alter database
create table
alter table
drop table
crate index
drop index
SQL
基础操作
创建数据库
mysql> create database test
查看数据库
mysql> show databases;
使用test数据库
mysql> use test
查看表
mysql> show tables;
一,基础教程
创建表
mysql> create table person (id int(4) not null primary key auto_increment,lastname varchar(20) not null,firstname varchar(20),age int(4),sex int(4) not null,address varchar(20));
插入数据
mysql> insert into person value (null,'hao','jery',13,1,'beijing');
删除一行数据
mysql> delete from person where id = 4;
查询去重
mysql> select distinct lastname from person;
where
mysql> select * from person where address = 'beijing';
and
mysql> select * from person where age>13 and age<26;
or
mysql> select * from person where age<20 or age >25;
order by
mysql> select * from person order by age;
mysql> select lastname,age from person order by age;
mysql> select lastname,age from person order by age asc; //顺序显示
mysql> select lastname,age from person order by age desc;//逆向显示
mysql> update person set lastname='zhuxiaoxiao' where lastname='du';
mysql> update person set lastname='update',age=27 where id = 12;
mysql> delete from person where lastname ='zhixiang';