Redhat7 安装mariadb（原mysql）

Redhat7 安装mariadb（原mysql）

安装：

# yum install mariadb mariadb-server

 

启动并开机启动：

# systemctl start mariadb

# systemctl enable mariadb

 

此时mysql的root密码为空

# mysql –u root

• user mysql;

• update user set password=password(‘123456’) where user=root;

• flush privileges;

• quit

 

开防火墙：

# firewall-cmd –permanent –add-service=mysql

# firewall-cmd --reload

 

 

# vi /etc/my.cnf  （mysqld下）

 

Skip-networking= 1         （关闭远程通过ip进行连接，默认是允许的）

 

:wq

 

link 模糊查询

link ‘%a%’   中间含字母a的

link ‘_a%’    以a结尾的

link ‘%a_’    以a开头的

 

语句示例（注意区分函数、字段、表名）：

 

select * from worker where sal >= 2500;

select * from worker where sal != 2500;

 

select * from worker where deptno in(2,4);

 

select * from worker where sal between 1500 and 2500;

 

select avg(sal) from worker;

select max(sal) from worker;

select min(sal) from worker;

 

select * from worker order by deptno;   （升序排列）

select * from worker order by deptno desc;  （降序排列）

 

select deptno,max(sal) from worker group by deptno;

 

 

create table test as select * from worker;

 

内连接：

select student,sno,student.sname,coll.cname from student join coll onstudent.cno=coll.con;

 

左外连接：

select s.sno,s.sname,c.cnamefrom student as s left join coll as c on s.cno=c.cno;

 

右连接：

select s.sno,s.sname,c.cnamefrom coll as c right join student as s on s.cno=c.cno;

本文转自linux博客51CTO博客，原文链接http://blog.51cto.com/yangzhiming/1721717如需转载请自行联系原作者

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