mysql数据库基础命令（一）
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#MySQL从入门到放弃
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用户与权限
创建用户
mysql>create user test identified by 'BaC321@#';
修改密码
##5.5版本及以前的命令
mysql>set password for test=passowrd('!1A@2#3');
##5.6及以上命令
mysql>update mysql.user set authentication_string=password('A1b2c3#!@') where user='test';
创建用户并授权
mysql>grant select,insert,update on student.* to test@localhost identified by 'A1b2c3#!@';
查看授权
mysql> show grants for test@localhost;
移除权限
mysql> revoke insert,update on student.* from test@localhost;
建库与表
创建库
mysql> create database student;
mysql> show databases;
创建表
mysql> use student;
mysql> create table T1 (name varchar(10) not null,sex varchar(10) not null);
##通过现有的表创建新表
mysql> create table T2 as select * from T1;
插入数据
插入数据 mysql> insert into T1 values('zhang','man'); Query OK, 1 row affected (0.03 sec) mysql> insert into T1 values('li','man'); Query OK, 1 row affected (0.03 sec) mysql> insert into T1 values('wang','man'); Query OK, 1 row affected (0.02 sec) mysql> insert into T1 values('zhao','women'); Query OK, 1 row affected (0.05 sec) ##需要注意的是如果列超过两列，就需要指定列字段名如下 mysql> insert into T1(name,sex) values('gege','man');
查询数据
查询数据 mysql> select user,host from mysql.user;
查看用户
mysql> select * from T1 where name like '%an%';
mysql> select * from T1 where age like '2%';
##匹配查询
mysql> select * from T1 order by name,age;
##查询排序
mysql> select count(*) as toaolcount from T1;
mysql> select sum(age) as sumvalue from T1;
mysql> select avg(age) as avgvalue from T1;
mysql> select max(age) from T1;
##查询值
mysql> select score from T1 where score <91;
mysql> select score from T1 where score >=91;
mysql> select * from T1 where score in (96,100);
##条件查询
mysql> select * from T2;
mysql> select * from T1;
增删更新
增加与删除列 mysql> alter table T1 add age int(4) not null; mysql> alter table T1 drop age 更新表里的数据 mysql> update T1 set age=25 where name='zhang'; mysql> update T1 set age=23 where name='li'; 删除数据 mysql> delete from T1 where age='22'; 建索引与删除 mysql> create index indexT1 on T1(name(10)); mysql> drop index indexT1 on T1;
主键与视图
创建主键
mysql> alter table T1 add primary key(name);
mysql> desc T1;
创建与删除视图
mysql> create view t1view as select name from T1;
mysql> select * from t1view;
mysql> drop view t1view;
mysql> select * from t1view;
ERROR 1146 (42S02): Table 'student.t1view' doesn't exist
###提示此视图不存在
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