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MySQL常用命令
MySQL常用命令
开发者必备Mysql常用命令,涵盖了数据定义语句、数据操纵语句及数据控制语句,基于Mysql5.7。
数据定义语句(DDL)
数据库操作
- 登录数据库:
mysql -uroot -proot
- 创建数据库:
create database test
- 查看所有数据库:
show databases
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- 选择数据库并使用:
use test
- 查看所有数据表:
show tables
- 删除数据库:
drop database test
表操作
- 创建表:
create table emp(ename varchar(10),hiredate date,sal decimal(10,2),deptno int(2))
create table dept(deptno int(2),deptname varchar(10))
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- 查看表的定义:
desc emp
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- 查看表定义(详细):
show create table emp \G
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- 删除表:
drop table emp
- 修改表字段:
alter table emp modify ename varchar(20)
- 添加表字段:
alter table emp add column age int(3)
- 删除表字段:
alter table emp drop column age
- 字段改名;
alter table emp change age age1 int(4)
- 修改表名:
alter table emp rename emp1
数据操纵语句(DML)
插入记录
- 指定名称插入:
insert into emp (ename,hiredate,sal,deptno) values ('zhangsan','2018-01-01','2000',1)
- 不指定名称插入:
insert into emp values ('lisi','2018-01-01','2000',1)
- 批量插入数据:
insert into dept values(1,'dept1'),(2,'dept2')
修改记录
update emp set sal='4000',deptno=2 where ename='zhangsan'
删除记录
delete from emp where ename='zhangsan'
查询记录
- 查询所有记录:
select * from emp
- 查询不重复的记录:
select distinct deptno from emp
- 条件查询:
select * from emp where deptno=1 and sal<3000
- 排序和限制:
select * from emp order by deptno desc limit 2
- 分页查询(查询从第0条记录开始10条):
select * from emp order by deptno desc limit 0,10
- 聚合(查询部门人数大于1的部门编号):
select deptno,count(1) from emp group by deptno having count(1) > 1
- 连接查询:
select * from emp e left join dept d on e.deptno=d.deptno
- 子查询:
select * from emp where deptno in (select deptno from dept)
- 记录联合:
select deptno from emp union select deptno from dept
数据控制语句(DCL)
权限相关
- 授予操作权限(将test数据库中所有表的select和insert权限授予test用户):
grant select,insert on test.* to 'test'@'localhost' identified by '123'
- 查看账号权限:
show grants for 'test'@'localhost'
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- 收回操作权限:
revoke insert on test.* from 'test'@'localhost'
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- 授予所有数据库的所有权限:
grant all privileges on *.* to 'test'@'localhost'
- 授予所有数据库的所有权限(包括grant):
grant all privileges on *.* to 'test'@'localhost' with grant option
- 授予SUPER PROCESS FILE权限(系统权限不能指定数据库):
grant super,process,file on *.* to 'test'@'localhost'
- 只授予登录权限:
grant usage on *.* to 'test'@'localhost'
帐号相关
- 删除账号:
drop user 'test'@'localhost'
- 修改自己的密码:
set password = password('123')
- 管理员修改他人密码:
set password for 'test'@'localhost' = password('123')
其他
字符集相关
- 查看字符集:
show variables like 'character%'
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- 创建数据库时指定字符集:
create database test2 character set utf8
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时区相关
- 查看当前时区(UTC为世界统一时间,中国为UTC+8):
show variables like "%time_zone%"
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- 修改mysql全局时区为北京时间,即我们所在的东8区:
set global time_zone = '+8:00';
- 修改当前会话时区:
set time_zone = '+8:00'
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- 立即生效:
flush privileges