Redhat7 安装mariadb（原mysql）

32饿1e

Redhat7 安装mariadb（原mysql）


安装：
# yuminstall 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 –uroot

• 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;

selectavg(sal) from worker;
selectmax(sal) from worker;
selectmin(sal) from worker;

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

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


createtable test as select * from worker;

内连接：
selectstudent,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;