linux系统mysql普通语句

SQL语句

1.语义

1.DDL	数据定义语言
2.DCL	数据控制语言
3.DML	数据操作语言
4.DQL	数据查询语言

一、DDL数据定义语言（create、drop）

1.create对库操作

#1.完整的建库语句
mysql> create database db5 character set=utf8 collate=utf8_general_ci;
Query OK, 1 row affected (0.00 sec)

#2.常用的建库语句
mysql> create database db6 charset utf8;
Query OK, 1 row affected (0.00 sec)

2.create对表的操作

#1.简单的建表语句
mysql> create table tb1 (id int);
Query OK, 0 rows affected (0.08 sec)

#2.数据类型
int				整数  -2^31 - 2^31-1    (-2147483648 - 2147483647)
tinyint			最小整数   -128 - 127	#年龄  0 - 255
varchar			字符类型（变长）	#身份证
char			字符类型（定长）
enum			枚举类型	#给它固定选项，只能选则选择项中的值    性别
datetime		时间类型	年月日时分秒

#3.建表语句
mysql> create table tb2 (id int,name varchar(12),age tinyint,sex enum('m','f'),cometime datetime);
Query OK, 0 rows affected (0.02 sec)

#4.数据属性
not null： 			#非空
primary key： 		#主键（唯一且非空的）
auto_increment： 	#自增（此列必须是：primary key或者unique key）
unique key： 		#唯一键，单独的唯一的
default： 			#默认值
unsigned： 			#非负数
comment： 			#注释

#5.结合数据属性建表
create table student (
id int primary key auto_increment comment "学生id",
name varchar(12) not null comment "学生姓名",
age tinyint unsigned not null comment "学生年龄",
gender enum('m','f') default 'f' comment "学生性别",
cometime datetime default now() comment "入学时间");

#6.修改表
mysql> alter table student add birthday datetime COMMENT '学生生日';
Query OK, 0 rows affected (0.04 sec)
Records: 0  Duplicates: 0  Warnings: 0

二、DCL数据控制语言（grant、revoke）

1.grant授权命令

#1.授权命令（没有grant权限）
mysql> grant all on *.* to root@'172.16.1.%' identified by '123';
Query OK, 0 rows affected (0.00 sec)

#2.全库全表授权
mysql> grant all on *.* to root@'172.16.1.%' identified by '123';
Query OK, 0 rows affected (0.00 sec)

#3.单库授权
mysql> grant all on mysql.* to root@'172.16.1.%' identified by '123';
Query OK, 0 rows affected (0.00 sec)

#4.单表授权
mysql> grant all on mysql.user to root@'172.16.1.%' identified by '123';
Query OK, 0 rows affected (0.00 sec)

#5.单列授权（脱敏）
mysql> grant select(user,host) on mysql.user to root@'172.16.1.%' identified by '123';
Query OK, 0 rows affected (0.00 sec)

#6.授权一个超级管理员
grant all on *.* to root@'172.16.1.%' identified by '123' with grant option;
Query OK, 0 rows affected (0.00 sec)

2.revoke回收权限

#1.回收权限
mysql> revoke drop,delete on *.* from root@'172.16.1.%';
Query OK, 0 rows affected (0.00 sec)

#2.查看用户权限
mysql> show grants for root@'172.16.1.%';

三、DML数据操作语言（insert、delete、update）

1.insert 命令

1）查看表结构

mysql> desc student;
+----------+---------------------+------+-----+-------------------+----------------+
| Field    | Type                | Null | Key | Default           | Extra          |
+----------+---------------------+------+-----+-------------------+----------------+
| id       | int(11)             | NO   | PRI | NULL              | auto_increment |
| name     | varchar(12)         | NO   |     | NULL              |                |
| age      | tinyint(3) unsigned | NO   |     | NULL              |                |
| gender   | enum('m','f')       | YES  |     | f                 |                |
| cometime | datetime            | YES  |     | CURRENT_TIMESTAMP |                |
| birthday | datetime            | YES  |     | NULL              |                |
+----------+---------------------+------+-----+-------------------+----------------+
6 rows in set (0.00 sec)

2）插入数据（不规范写法）

mysql> insert into student values(1,'邱导',78,'f',now(),'1942-07-14');
Query OK, 1 row affected (0.00 sec)

mysql> select * from student;
+----+--------+-----+--------+---------------------+---------------------+
| id | name   | age | gender | cometime            | birthday            |
+----+--------+-----+--------+---------------------+---------------------+
|  1 | 邱导   |  78 | f      | 2020-07-15 09:21:12 | 1942-07-14 00:00:00 |
+----+--------+-----+--------+---------------------+---------------------+
1 row in set (0.00 sec)

3）插入数据（规范写法）

#1.插入指定列数据
mysql> insert into student(name,age) values('曾导','84');
Query OK, 1 row affected (0.00 sec)

mysql> select * from student;
+----+--------+-----+--------+---------------------+---------------------+
| id | name   | age | gender | cometime            | birthday            |
+----+--------+-----+--------+---------------------+---------------------+
|  1 | 邱导   |  78 | f      | 2020-07-15 09:21:12 | 1942-07-14 00:00:00 |
|  2 | 邱导   |  78 | f      | 2020-07-15 09:22:27 | 1942-07-14 00:00:00 |
|  3 | 曾导   |  84 | f      | 2020-07-15 09:24:17 | NULL                |
+----+--------+-----+--------+---------------------+---------------------+
3 rows in set (0.00 sec)

#2.插入指定列数据
mysql> insert into student(name,age,birthday) values('曾导','84','1936-02-20');
Query OK, 1 row affected (0.00 sec)

mysql> select * from student;
+----+--------+-----+--------+---------------------+---------------------+
| id | name   | age | gender | cometime            | birthday            |
+----+--------+-----+--------+---------------------+---------------------+
|  1 | 邱导   |  78 | f      | 2020-07-15 09:21:12 | 1942-07-14 00:00:00 |
|  2 | 邱导   |  78 | f      | 2020-07-15 09:22:27 | 1942-07-14 00:00:00 |
|  3 | 曾导   |  84 | f      | 2020-07-15 09:24:17 | NULL                |
|  4 | 曾导   |  84 | f      | 2020-07-15 09:25:22 | 1936-02-20 00:00:00 |
+----+--------+-----+--------+---------------------+---------------------+
4 rows in set (0.00 sec)

4）插入多条数据

mysql> insert into student(name,age,birthday) values('好大','18',1936-02-21),('好小','28','1992-01-01');
Query OK, 2 rows affected, 1 warning (0.00 sec)
Records: 2  Duplicates: 0  Warnings: 1

mysql> select * from student;
+----+--------+-----+--------+---------------------+---------------------+
| id | name   | age | gender | cometime            | birthday            |
+----+--------+-----+--------+---------------------+---------------------+
|  1 | 邱导   |  78 | f      | 2020-07-15 09:21:12 | 1942-07-14 00:00:00 |
|  2 | 邱导   |  78 | f      | 2020-07-15 09:22:27 | 1942-07-14 00:00:00 |
|  3 | 曾导   |  84 | f      | 2020-07-15 09:24:17 | NULL                |
|  4 | 曾导   |  84 | f      | 2020-07-15 09:25:22 | 1936-02-20 00:00:00 |
|  5 | 曾导   |  84 | f      | 2020-07-15 09:28:11 | 1936-02-21 00:00:00 |
|  6 | 好大   |  18 | f      | 2020-07-15 09:29:18 | 0000-00-00 00:00:00 |
|  7 | 好大   |  18 | f      | 2020-07-15 09:31:07 | 0000-00-00 00:00:00 |
|  8 | 好小   |  28 | f      | 2020-07-15 09:31:07 | 1992-01-01 00:00:00 |
+----+--------+-----+--------+---------------------+---------------------+
8 rows in set (0.00 sec)

2.update命令

1）查看数据

mysql> select * from student;
+----+--------+-----+--------+---------------------+---------------------+
| id | name   | age | gender | cometime            | birthday            |
+----+--------+-----+--------+---------------------+---------------------+
|  1 | 邱导   |  78 | f      | 2020-07-15 09:21:12 | 1942-07-14 00:00:00 |
|  2 | 邱导   |  78 | f      | 2020-07-15 09:22:27 | 1942-07-14 00:00:00 |
|  3 | 曾导   |  84 | f      | 2020-07-15 09:24:17 | NULL                |
|  4 | 曾导   |  84 | f      | 2020-07-15 09:25:22 | 1936-02-20 00:00:00 |
|  5 | 曾导   |  84 | f      | 2020-07-15 09:28:11 | 1936-02-21 00:00:00 |
|  6 | 好大   |  18 | f      | 2020-07-15 09:29:18 | 0000-00-00 00:00:00 |
|  7 | 好大   |  18 | f      | 2020-07-15 09:31:07 | 0000-00-00 00:00:00 |
|  8 | 好小   |  28 | f      | 2020-07-15 09:31:07 | 1992-01-01 00:00:00 |
+----+--------+-----+--------+---------------------+---------------------+
8 rows in set (0.00 sec)

2）修改数据

#使用update语句必须要加where条件
mysql> update student set age=18 where name='邱导';
Query OK, 2 rows affected (0.01 sec)
Rows matched: 2  Changed: 2  Warnings: 0

mysql> select * from student;
+----+--------+-----+--------+---------------------+---------------------+
| id | name   | age | gender | cometime            | birthday            |
+----+--------+-----+--------+---------------------+---------------------+
|  1 | 邱导   |  18 | f      | 2020-07-15 09:21:12 | 1942-07-14 00:00:00 |
|  2 | 邱导   |  18 | f      | 2020-07-15 09:22:27 | 1942-07-14 00:00:00 |
|  3 | 曾导   |  84 | f      | 2020-07-15 09:24:17 | NULL                |
|  4 | 曾导   |  84 | f      | 2020-07-15 09:25:22 | 1936-02-20 00:00:00 |
|  5 | 曾导   |  84 | f      | 2020-07-15 09:28:11 | 1936-02-21 00:00:00 |
|  6 | 好大   |  18 | f      | 2020-07-15 09:29:18 | 0000-00-00 00:00:00 |
|  7 | 好大   |  18 | f      | 2020-07-15 09:31:07 | 0000-00-00 00:00:00 |
|  8 | 好小   |  28 | f      | 2020-07-15 09:31:07 | 1992-01-01 00:00:00 |
+----+--------+-----+--------+---------------------+---------------------+
8 rows in set (0.00 sec)

3）指点修改一条数据

#如果数据库有主键，一定使用主键
mysql> update student set age=88 where name='邱导' and cometime='2020-07-15 09:21:12';
Query OK, 1 row affected (0.00 sec)
Rows matched: 1  Changed: 1  Warnings: 0

mysql> update student set age=88 where id=2;
Query OK, 1 row affected (0.00 sec)
Rows matched: 1  Changed: 1  Warnings: 0

mysql> select * from student;
+----+--------+-----+--------+---------------------+---------------------+
| id | name   | age | gender | cometime            | birthday            |
+----+--------+-----+--------+---------------------+---------------------+
|  1 | 邱导   |  88 | f      | 2020-07-15 09:21:12 | 1942-07-14 00:00:00 |
|  2 | 邱导   |  88 | f      | 2020-07-15 09:22:27 | 1942-07-14 00:00:00 |
|  3 | 曾导   |  84 | f      | 2020-07-15 09:24:17 | NULL                |
|  4 | 曾导   |  84 | f      | 2020-07-15 09:25:22 | 1936-02-20 00:00:00 |
|  5 | 曾导   |  84 | f      | 2020-07-15 09:28:11 | 1936-02-21 00:00:00 |
|  6 | 好大   |  18 | f      | 2020-07-15 09:29:18 | 0000-00-00 00:00:00 |
|  7 | 好大   |  18 | f      | 2020-07-15 09:31:07 | 0000-00-00 00:00:00 |
|  8 | 好小   |  28 | f      | 2020-07-15 09:31:07 | 1992-01-01 00:00:00 |
+----+--------+-----+--------+---------------------+---------------------+
8 rows in set (0.00 sec)

3.delete语句

1）删除数据

#1.先查看数据，确认要删除的数据，怎么确定唯一

#2.使用delete语句也一定要加where条件
mysql> delete from student where id=8;
Query OK, 1 row affected (0.01 sec)

mysql> select * from student;
+----+--------+-----+--------+---------------------+---------------------+
| id | name   | age | gender | cometime            | birthday            |
+----+--------+-----+--------+---------------------+---------------------+
|  1 | 邱导   |  88 | f      | 2020-07-15 09:21:12 | 1942-07-14 00:00:00 |
|  2 | 邱导   |  88 | f      | 2020-07-15 09:22:27 | 1942-07-14 00:00:00 |
|  3 | 曾导   |  84 | f      | 2020-07-15 09:24:17 | NULL                |
|  4 | 曾导   |  84 | f      | 2020-07-15 09:25:22 | 1936-02-20 00:00:00 |
|  5 | 曾导   |  84 | f      | 2020-07-15 09:28:11 | 1936-02-21 00:00:00 |
|  6 | 好大   |  18 | f      | 2020-07-15 09:29:18 | 0000-00-00 00:00:00 |
|  7 | 好大   |  18 | f      | 2020-07-15 09:31:07 | 0000-00-00 00:00:00 |
+----+--------+-----+--------+---------------------+---------------------+
7 rows in set (0.00 sec)

#3.如果就是要清空表
mysql> delete from student where 1=1;
Query OK, 1 row affected (0.01 sec)
#(危险)
truncate table student;
drop table student

4.使用update代替delete

1）添加状态字段

mysql> alter table student add status enum('1','0') default 1;
Query OK, 0 rows affected (0.08 sec)
Records: 0  Duplicates: 0  Warnings: 0

mysql> select * from student;
+----+--------+-----+--------+---------------------+---------------------+--------+
| id | name   | age | gender | cometime            | birthday            | status |
+----+--------+-----+--------+---------------------+---------------------+--------+
|  1 | 邱导   |  88 | f      | 2020-07-15 09:21:12 | 1942-07-14 00:00:00 | 1      |
|  2 | 邱导   |  88 | f      | 2020-07-15 09:22:27 | 1942-07-14 00:00:00 | 1      |
|  3 | 曾导   |  84 | f      | 2020-07-15 09:24:17 | NULL                | 1      |
|  4 | 曾导   |  84 | f      | 2020-07-15 09:25:22 | 1936-02-20 00:00:00 | 1      |
|  5 | 曾导   |  84 | f      | 2020-07-15 09:28:11 | 1936-02-21 00:00:00 | 1      |
|  6 | 好大   |  18 | f      | 2020-07-15 09:29:18 | 0000-00-00 00:00:00 | 1      |
|  7 | 好大   |  18 | f      | 2020-07-15 09:31:07 | 0000-00-00 00:00:00 | 1      |
+----+--------+-----+--------+---------------------+---------------------+--------+
7 rows in set (0.00 sec)

2）使用update代替delete

#相当于删除学生
mysql> update student set status='0' where id =2;
Query OK, 1 row affected (0.00 sec)
Rows matched: 1  Changed: 1  Warnings: 0

mysql> select * from student;
+----+--------+-----+--------+---------------------+---------------------+--------+
| id | name   | age | gender | cometime            | birthday            | status |
+----+--------+-----+--------+---------------------+---------------------+--------+
|  2 | 邱导   |  88 | f      | 2020-07-15 09:22:27 | 1942-07-14 00:00:00 | 0      |
|  3 | 曾导   |  84 | f      | 2020-07-15 09:24:17 | NULL                | 1      |
|  4 | 曾导   |  84 | f      | 2020-07-15 09:25:22 | 1936-02-20 00:00:00 | 1      |
|  5 | 曾导   |  84 | f      | 2020-07-15 09:28:11 | 1936-02-21 00:00:00 | 1      |
|  6 | 好大   |  18 | f      | 2020-07-15 09:29:18 | 0000-00-00 00:00:00 | 1      |
|  7 | 好大   |  18 | f      | 2020-07-15 09:31:07 | 0000-00-00 00:00:00 | 1      |
+----+--------+-----+--------+---------------------+---------------------+--------+
6 rows in set (0.00 sec)

#相当于学生回来
mysql> update student set status='1' where id =2;
Query OK, 1 row affected (0.00 sec)
Rows matched: 1  Changed: 1  Warnings: 0

mysql> select * from student;
+----+--------+-----+--------+---------------------+---------------------+--------+
| id | name   | age | gender | cometime            | birthday            | status |
+----+--------+-----+--------+---------------------+---------------------+--------+
|  2 | 邱导   |  88 | f      | 2020-07-15 09:22:27 | 1942-07-14 00:00:00 | 1      |
|  3 | 曾导   |  84 | f      | 2020-07-15 09:24:17 | NULL                | 1      |
|  4 | 曾导   |  84 | f      | 2020-07-15 09:25:22 | 1936-02-20 00:00:00 | 1      |
|  5 | 曾导   |  84 | f      | 2020-07-15 09:28:11 | 1936-02-21 00:00:00 | 1      |
|  6 | 好大   |  18 | f      | 2020-07-15 09:29:18 | 0000-00-00 00:00:00 | 1      |
|  7 | 好大   |  18 | f      | 2020-07-15 09:31:07 | 0000-00-00 00:00:00 | 1      |
+----+--------+-----+--------+---------------------+---------------------+--------+
6 rows in set (0.00 sec)

四、DQL数据查询语言（select、desc）

1.select查询语句

1）查询表中所有的数据

#很危险，数据量过大，容易导致down机
mysql> select * from student;

#先查询数据总量，然后决定是否可以查询所有数据
mysql> select count(*) from student;
+----------+
| count(*) |
+----------+
|        6 |
+----------+
1 row in set (0.01 sec)

2）查看指定列的数据

mysql> select user,host from mysql.user;
+--------+------------+
| user   | host       |
+--------+------------+
| root   | %          |
| root   | 127.0.0.1  |
| lhd    | 172.16.1.% |
| qiudao | 172.16.1.% |
| root   | 172.16.1.% |
| root   | ::1        |
|        | db03       |
| root   | db03       |
|        | localhost  |
| root   | localhost  |
+--------+------------+
10 rows in set (0.01 sec)

3）按条件查询

mysql> select name,gender from student where name='邱导';
+--------+--------+
| name   | gender |
+--------+--------+
| 邱导   | f      |
+--------+--------+
1 row in set (0.00 sec)

2.简单查询练习

1）将sql文件导入数据

#方式一：
[root@db03 ~]# mysql -uroot -p123 < world.sql 

#方式二:
mysql> source /root/world.sql;

#方式三:
mysql> . /root/world.sql;

2）查看数据

mysql> use world;
Database changed
mysql> show tables;
+-----------------+
| Tables_in_world |
+-----------------+
| city            |
| country         |
| countrylanguage |
+-----------------+
3 rows in set (0.00 sec)

mysql> select count(*) from city;
+----------+
| count(*) |
+----------+
|     4079 |
+----------+
1 row in set (0.00 sec)

mysql> select * from city;

3）查询练习

#1.查看表结构
mysql> desc city;
+-------------+----------+------+-----+---------+----------------+
| Field       | Type     | Null | Key | Default | Extra          |
+-------------+----------+------+-----+---------+----------------+
| ID          | int(11)  | NO   | PRI | NULL    | auto_increment |
| Name        | char(35) | NO   |     |         |                |
| CountryCode | char(3)  | NO   | MUL |         |                |
| District    | char(20) | NO   |     |         |                |
| Population  | int(11)  | NO   |     | 0       |                |
+-------------+----------+------+-----+---------+----------------+
5 rows in set (0.00 sec)

#2.查看所有数据
mysql> select * from city;

#3.查看指定列的数据
mysql> select Name,Population from city;

#4.查看数据时排序（按照人口数量）
#升序
mysql> select Name,Population from city order by Population;
#降序
mysql> select Name,Population from city order by Population desc;

#5.查询部分数据
#查看前十条数据
mysql> select Name,Population from city order by Population desc limit 10;

#6.按照步长查询数据
mysql> select id,Name,Population from city limit 50,50;
										#50起始位置  50步长

3.条件查询

#1.条件查询就是使用where语句，where语句可以使用的符号
条件符号：= < > <= >= != <> or and like
	精确匹配：=
	范围匹配：< > <= >= != <>
	模糊匹配：like
	连接语句：or and
	
#2.查询中国的城市人口
mysql> select name,population from city where CountryCode='CHN';

#3.查询黑龙江人口数量
mysql> select name,population from city where countrycode='CHN' and District='heilongjiang';

#4.查询中国人口数量小于100000的城市
mysql> select name,population from city where countrycode='CHN' and population < 100000;

#5.模糊匹配
#匹配以N结尾的数据
mysql> select name,countrycode from city where countrycode like '%N';
#匹配以N开头的数据
mysql> select name,countrycode from city where countrycode like 'N%';
#匹配包含N的数据
mysql> select name,countrycode from city where countrycode like '%N%';

#6.查询中国或美国的人口数量
#使用or
mysql> select name,population from city where countrycode = 'CHN' or countrycode = 'USA';
#使用in
mysql> select name,population from city where countrycode in ('CHN','USA');
#使用union all
mysql> select name,population from city where countrycode = 'CHN' union all select name,population from city where countrycode = 'USA';

五、select高级用法

#多表联查，联表查询

1.传统连接

1）集合

#集合
[qiudao,zengdao,qiandao]
[80,90,100]

#数据库
id:[1,2,3]
name:[qiudao,zengdao,qiandao]

id:[1,2,3]
mark:[80,90,100]

2）建表

mysql> create table students(id int,name varchar(10));
Query OK, 0 rows affected (0.08 sec)

mysql> create table score(id int,mark int);
Query OK, 0 rows affected (0.05 sec)

3）插入数据

mysql> insert into students values(1,'qiudao'),(2,'qiandao'),(3,'zengdao');
Query OK, 3 rows affected (0.02 sec)
Records: 3  Duplicates: 0  Warnings: 0

mysql> insert into score values(1,80),(2,90),(3,100);
Query OK, 3 rows affected (0.01 sec)
Records: 3  Duplicates: 0  Warnings: 0

4）数据查询

#查看两个表的数据
mysql> select * from students;
+------+---------+
| id   | name    |
+------+---------+
|    1 | qiudao  |
|    2 | qiandao |
|    3 | zengdao |
+------+---------+
3 rows in set (0.00 sec)

mysql> select * from score;
+------+------+
| id   | mark |
+------+------+
|    1 |   80 |
|    2 |   90 |
|    3 |  100 |
+------+------+
3 rows in set (0.00 sec)

#查看邱导的分数
mysql> select students.name,score.mark from students,score where students.id=1 and score.id=1;

mysql> select students.name,score.mark from students,score where students.id=score.id and name='qiudao';
+--------+------+
| name   | mark |
+--------+------+
| qiudao |   80 |
+--------+------+
1 row in set (0.01 sec)

#查询所有学生成绩
mysql> select students.name,score.mark from students,score where students.id=score.id

5）练习题一：

连表查询：世界上小于100人的城市在哪个国家？请列出城市名字，国家名字与人口数量

#1.确认我要查哪些内容
国家名字  城市名字  城市人口数量   小于100人

#2.确认在哪个表
country.name   city.name   city.population   

#3.找出两个表相关联的字段
city.countrycode   country.code

#4.编写语句
mysql> select country.name,city.name,city.population from country,city where city.countrycode=country.code and city.population < 100;
+----------+-----------+------------+
| name     | name      | population |
+----------+-----------+------------+
| Pitcairn | Adamstown |         42 |
+----------+-----------+------------+
1 row in set (0.01 sec)

6）练习题二：

连表查询：世界上小于100人的城市在哪个国家，是用什么语言？请列出城市名字，国家名字与人口数量和国家语言

#1.确认我要查哪些内容
国家名字  城市名字  城市人口数量   国家使用的语言   小于100人

#2.确认在哪个表
country.name   city.name   city.population   countrylanguage.language

#3.找出三个表相关联的字段
country.code   city.countrycode   countrylanguage.countrycode

#4.写sql语句
mysql> select country.name,city.name,city.population,countrylanguage.language from country,city,countrylanguage where country.code=city.countrycode and city.countrycode=countrylanguage.countrycode and city.population < 100;
+----------+-----------+------------+-------------+
| name     | name      | population | language    |
+----------+-----------+------------+-------------+
| Pitcairn | Adamstown |         42 | Pitcairnese |
+----------+-----------+------------+-------------+
1 row in set (0.04 sec)

2.自连接

#自己查找相同字段，使用自连接，两个关联的表必须有相同字段和相同数据
SELECT city.name,city.countrycode,countrylanguage.language,city.population
FROM  city NATURAL JOIN countrylanguage 
WHERE population > 1000000
ORDER BY population;

#两个表中没有相同字段不行，字段相同值不同不行
SELECT country.name,city.name,city.population FROM city NATURAL JOIN country WHERE population < 100;

#注意：
1.自连接必须有相同字段和相同值
2.两个表中的数据必须完全相同