第八章| 2. MySQL数据库|数据操作| 权限管理
1、数据操作
SQL（结构化查询语言），可以操作关系型数据库
通过sql可以创建、修改账号并控制账号权限； 通过sql可以创建、修改数据库、表； 通过sql可以增删改查数据；
可以通过SQL语句中的DML语言来实现数据的操作，包括
- 使用INSERT实现数据的插入
- UPDATE实现数据的更新
- 使用DELETE实现数据的删除
- 使用SELECT查询数据以及。
1.1数据的增删改查
插入数据INSERT . 插入完整数据（顺序插入）
语法一：
INSERT INTO 表名(字段1,字段2,字段3…字段n) VALUES(值1,值2,值3…值n);
语法二：
INSERT INTO 表名 VALUES (值1,值2,值3…值n); . 指定字段插入数据
语法：
INSERT INTO 表名(字段1,字段2,字段3…) VALUES (值1,值2,值3…); . 插入多条记录
语法：
INSERT INTO 表名 VALUES
(值1,值2,值3…值n),
(值1,值2,值3…值n),
(值1,值2,值3…值n); . 插入查询结果
语法：
INSERT INTO 表名(字段1,字段2,字段3…字段n)
SELECT (字段1,字段2,字段3…字段n) FROM 表2
WHERE …;
更新数据UPDATE
语法：
UPDATE 表名 SET
字段1=值1,
字段2=值2,
WHERE CONDITION;
示例：
UPDATE mysql.user SET password=password(‘’)
where user=’root’ and host=’localhost’; 删除数据DELETE
语法：
DELETE FROM 表名
WHERE CONITION;
示例：
DELETE FROM mysql.user
WHERE password=’’; 练习：
更新MySQL root用户密码为mysql123
删除除从本地登录的root用户以外的所有用户
1.2单表查询
把表中所有行和列都列举出来使用“*” 来表示所有的列如select * from student;
查询部分行和列需要列举不同的列名，而查询部分分行需要where子句进行条件限制，如select studentNo,studentName,address from student where address = '河南新乡';
在查询中使用列的别名，AS子句可以用来改变结果集中列的名称，也可以为组合或计算出的列指定名称，让标题列的信息更易懂。如select studentNo AS 学生编号，studentName as 学生姓名，address as 学生地址 from student where address = ‘河南新乡’; 还有一种情况是为通过计算、合并得到的新列命名 如select firstName+ ‘.’+lastName as 姓名 from employee
单表查询 select distinct 字段1,字段2,字段3 from 库.表
where 条件
group by 分组条件
having 过滤 having运行完之后不是去运行order，而是去运行distinct后边的字段，进行去重；distinct运行完之后再运行order by
order by 排序字段
limit n; 最后再运行limit
#########简单查询
mysql> use db5;
Database changed
mysql> desc employee;
+--------------+-----------------------+------+-----+---------+----------------+
| Field | Type | Null | Key | Default | Extra |
+--------------+-----------------------+------+-----+---------+----------------+
| id | int(11) | NO | PRI | NULL | auto_increment |
| name | varchar(20) | NO | | NULL | |
| sex | enum('male','female') | NO | | male | |
| age | int(3) unsigned | NO | | 28 | |
| hire_date | date | NO | | NULL | |
| post | varchar(50) | YES | | NULL | |
| post_comment | varchar(100) | YES | | NULL | |
| salary | double(15,2) | YES | | NULL | |
| office | int(11) | YES | | NULL | |
| depart_id | int(11) | YES | | NULL | |
+--------------+-----------------------+------+-----+---------+----------------+
10 rows in set (0.16 sec) mysql> select * from employee;
+----+------------+--------+-----+------------+-----------------------------------------+--------------+------------+--------+-----------+
| id | name | sex | age | hire_date | post | post_comment | salary | office | depart_id |
+----+------------+--------+-----+------------+-----------------------------------------+--------------+------------+--------+-----------+
| 1 | egon | male | 18 | 2017-03-01 | 老男孩驻沙河办事处外交大使 | NULL | 7300.33 | 401 | 1 |
| 2 | alex | male | 78 | 2015-03-02 | teacher | NULL | 1000000.31 | 401 | 1 |
| 3 | wupeiqi | male | 81 | 2013-03-05 | teacher | NULL | 8300.00 | 401 | 1 |
| 4 | yuanhao | male | 73 | 2014-07-01 | teacher | NULL | 3500.00 | 401 | 1 |
| 5 | liwenzhou | male | 28 | 2012-11-01 | teacher | NULL | 2100.00 | 401 | 1 |
| 6 | jingliyang | female | 18 | 2011-02-11 | teacher | NULL | 9000.00 | 401 | 1 |
| 7 | jinxin | male | 18 | 1900-03-01 | teacher | NULL | 30000.00 | 401 | 1 |
| 8 | 成龙 | male | 48 | 2010-11-11 | teacher | NULL | 10000.00 | 401 | 1 |
| 9 | 歪歪 | female | 48 | 2015-03-11 | sale | NULL | 3000.13 | 402 | 2 |
| 10 | 丫丫 | female | 38 | 2010-11-01 | sale | NULL | 2000.35 | 402 | 2 |
| 11 | 丁丁 | female | 18 | 2011-03-12 | sale | NULL | 1000.37 | 402 | 2 |
| 12 | 星星 | female | 18 | 2016-05-13 | sale | NULL | 3000.29 | 402 | 2 |
| 13 | 格格 | female | 28 | 2017-01-27 | sale | NULL | 4000.33 | 402 | 2 |
| 14 | 张野 | male | 28 | 2016-03-11 | operation | NULL | 10000.13 | 403 | 3 |
| 15 | 程咬金 | male | 18 | 1997-03-12 | operation | NULL | 20000.00 | 403 | 3 |
| 16 | 程咬银 | female | 18 | 2013-03-11 | operation | NULL | 19000.00 | 403 | 3 |
| 17 | 程咬铜 | male | 18 | 2015-04-11 | operation | NULL | 18000.00 | 403 | 3 |
| 18 | 程咬铁 | female | 18 | 2014-05-12 | operation | NULL | 17000.00 | 403 | 3 |
+----+------------+--------+-----+------------+-----------------------------------------+--------------+------------+--------+-----------+
18 rows in set (0.00 sec)
mysql> select id,name,salary from employee;
+----+------------+------------+
| id | name | salary |
+----+------------+------------+
| | egon | 7300.33 |
| | alex | 1000000.31 |
| | wupeiqi | 8300.00 |
| | yuanhao | 3500.00 |
| | liwenzhou | 2100.00 |
| | jingliyang | 9000.00 |
| | jinxin | 30000.00 |
| | 成龙 | 10000.00 |
| | 歪歪 | 3000.13 |
| | 丫丫 | 2000.35 |
| | 丁丁 | 1000.37 |
| | 星星 | 3000.29 |
| | 格格 | 4000.33 |
| | 张野 | 10000.13 |
| | 程咬金 | 20000.00 |
| | 程咬银 | 19000.00 |
| | 程咬铜 | 18000.00 |
| | 程咬铁 | 17000.00 |
+----+------------+------------+
rows in set (0.00 sec) mysql> select post from employee;
+-----------------------------------------+
| post |
+-----------------------------------------+
| 老男孩驻沙河办事处外交大使 |
| teacher |
| teacher |
| teacher |
| teacher |
| teacher |
| teacher |
| teacher |
| sale |
| sale |
| sale |
| sale |
| sale |
| operation |
| operation |
| operation |
| operation |
| operation |
+-----------------------------------------+
rows in set (0.00 sec) mysql> select distinct post from employee; ##distinct是避免重复
+-----------------------------------------+
| post |
+-----------------------------------------+
| 老男孩驻沙河办事处外交大使 |
| teacher |
| sale |
| operation |
+-----------------------------------------+
rows in set (0.08 sec) mysql> select name,salary*12 from employee; ##通过四则运算查询
+------------+-------------+
| name | salary* |
+------------+-------------+
| egon | 87603.96 |
| alex | 12000003.72 |
| wupeiqi | 99600.00 |
| yuanhao | 42000.00 |
| liwenzhou | 25200.00 |
| jingliyang | 108000.00 |
| jinxin | 360000.00 |
| 成龙 | 120000.00 |
| 歪歪 | 36001.56 |
| 丫丫 | 24004.20 |
| 丁丁 | 12004.44 |
| 星星 | 36003.48 |
| 格格 | 48003.96 |
| 张野 | 120001.56 |
| 程咬金 | 240000.00 |
| 程咬银 | 228000.00 |
| 程咬铜 | 216000.00 |
| 程咬铁 | 204000.00 |
+------------+-------------+
rows in set (0.09 sec) mysql> select name,salary* annual_salary from employee;
+------------+---------------+
| name | annual_salary |
+------------+---------------+
| egon | 87603.96 |
| alex | 12000003.72 |
| wupeiqi | 99600.00 |
| yuanhao | 42000.00 |
| liwenzhou | 25200.00 |
| jingliyang | 108000.00 |
| jinxin | 360000.00 |
| 成龙 | 120000.00 |
| 歪歪 | 36001.56 |
| 丫丫 | 24004.20 |
| 丁丁 | 12004.44 |
| 星星 | 36003.48 |
| 格格 | 48003.96 |
| 张野 | 120001.56 |
| 程咬金 | 240000.00 |
| 程咬银 | 228000.00 |
| 程咬铜 | 216000.00 |
| 程咬铁 | 204000.00 |
+------------+---------------+
rows in set (0.00 sec) mysql> select concat('姓名:', name, '性别:', sex)as info from employee; ##concat通常用于连接字符串
+--------------------------------+
| info |
+--------------------------------+
| 姓名:egon性别:male |
| 姓名:alex性别:male |
| 姓名:wupeiqi性别:male |
| 姓名:yuanhao性别:male |
| 姓名:liwenzhou性别:male |
| 姓名:jingliyang性别:female |
| 姓名:jinxin性别:male |
| 姓名:成龙性别:male |
| 姓名:歪歪性别:female |
| 姓名:丫丫性别:female |
| 姓名:丁丁性别:female |
| 姓名:星星性别:female |
| 姓名:格格性别:female |
| 姓名:张野性别:male |
| 姓名:程咬金性别:male |
| 姓名:程咬银性别:female |
| 姓名:程咬铜性别:male |
| 姓名:程咬铁性别:female |
+--------------------------------+
rows in set (0.14 sec) mysql> select concat('姓名:', name, '性别:', sex) as info, concat('年薪:', salar
y*) as annual_salary from employee;
+--------------------------------+--------------------+
| info | annual_salary |
+--------------------------------+--------------------+
| 姓名:egon性别:male | 年薪:87603.96 |
| 姓名:alex性别:male | 年薪:12000003.72 |
| 姓名:wupeiqi性别:male | 年薪:99600.00 |
| 姓名:yuanhao性别:male | 年薪:42000.00 |
| 姓名:liwenzhou性别:male | 年薪:25200.00 |
| 姓名:jingliyang性别:female | 年薪:108000.00 |
| 姓名:jinxin性别:male | 年薪:360000.00 |
| 姓名:成龙性别:male | 年薪:120000.00 |
| 姓名:歪歪性别:female | 年薪:36001.56 |
| 姓名:丫丫性别:female | 年薪:24004.20 |
| 姓名:丁丁性别:female | 年薪:12004.44 |
| 姓名:星星性别:female | 年薪:36003.48 |
| 姓名:格格性别:female | 年薪:48003.96 |
| 姓名:张野性别:male | 年薪:120001.56 |
| 姓名:程咬金性别:male | 年薪:240000.00 |
| 姓名:程咬银性别:female | 年薪:228000.00 |
| 姓名:程咬铜性别:male | 年薪:216000.00 |
| 姓名:程咬铁性别:female | 年薪:204000.00 |
+--------------------------------+--------------------+
rows in set (0.00 sec)
mysql> select concat(name, ':', age) from employee;
+------------------------+
| concat(name, ':', age) |
+------------------------+
| egon: |
| alex: |
| wupeiqi: |
| yuanhao: |
| liwenzhou: |
| jingliyang: |
| jinxin: |
| 成龙: |
| 歪歪: |
| 丫丫: |
| 丁丁: |
| 星星: |
| 格格: |
| 张野: |
| 程咬金: |
| 程咬银: |
| 程咬铜: |
| 程咬铁: |
+------------------------+
rows in set (0.00 sec) mysql> select concat_ws(':', name, sex, age) from employee; ##concat_ws（）第一个参数为分隔符
+--------------------------------+
| concat_ws(':', name, sex, age) |
+--------------------------------+
| egon:male: |
| alex:male: |
| wupeiqi:male: |
| yuanhao:male: |
| liwenzhou:male: |
| jingliyang:female: |
| jinxin:male: |
| 成龙:male: |
| 歪歪:female: |
| 丫丫:female: |
| 丁丁:female: |
| 星星:female: |
| 格格:female: |
| 张野:male: |
| 程咬金:male: |
| 程咬银:female: |
| 程咬铜:male: |
| 程咬铁:female: |
+--------------------------------+
rows in set (0.00 sec)
练习：
1 查出所有员工的名字，薪资,格式为
<名字:egon> <薪资:3000>
2 查出所有的岗位（去掉重复）
3 查出所有员工名字，以及他们的年薪,年薪的字段名为annual_year
mysql> select concat('<名字>:', name, '>')from employee;
+--------------------------------+
| concat('<名字>:', name, '>') |
+--------------------------------+
| <名字>:egon> |
| <名字>:alex> |
| <名字>:wupeiqi> |
| <名字>:yuanhao> |
| <名字>:liwenzhou> |
| <名字>:jingliyang> |
| <名字>:jinxin> |
| <名字>:成龙> |
| <名字>:歪歪> |
| <名字>:丫丫> |
| <名字>:丁丁> |
| <名字>:星星> |
| <名字>:格格> |
| <名字>:张野> |
| <名字>:程咬金> |
| <名字>:程咬银> |
| <名字>:程咬铜> |
| <名字>:程咬铁> |
+--------------------------------+
rows in set (0.00 sec)
mysql> select concat('<名字>:', name, '>'), concat('<薪资:', salary, '>') from employee;
+--------------------------------+---------------------------------+
| concat('<名字>:', name, '>') | concat('<薪资:', salary, '>') |
+--------------------------------+---------------------------------+
| <名字>:egon> | <薪资:7300.33> |
| <名字>:alex> | <薪资:1000000.31> |
| <名字>:wupeiqi> | <薪资:8300.00> |
| <名字>:yuanhao> | <薪资:3500.00> |
| <名字>:liwenzhou> | <薪资:2100.00> |
| <名字>:jingliyang> | <薪资:9000.00> |
| <名字>:jinxin> | <薪资:30000.00> |
| <名字>:成龙> | <薪资:10000.00> |
| <名字>:歪歪> | <薪资:3000.13> |
| <名字>:丫丫> | <薪资:2000.35> |
| <名字>:丁丁> | <薪资:1000.37> |
| <名字>:星星> | <薪资:3000.29> |
| <名字>:格格> | <薪资:4000.33> |
| <名字>:张野> | <薪资:10000.13> |
| <名字>:程咬金> | <薪资:20000.00> |
| <名字>:程咬银> | <薪资:19000.00> |
| <名字>:程咬铜> | <薪资:18000.00> |
| <名字>:程咬铁> | <薪资:17000.00> |
+--------------------------------+---------------------------------+
rows in set (0.00 sec)
#where约束
select id,name,age from employee where id > 7; #单条件 select name,post,salary from employee where post='teacher' and salary > 8000; select name,salary from employee where salary >= 20000 and salary <= 30000;
select name,salary from employee where salary between 20000 and 30000; select name,salary from employee where salary < 20000 or salary > 30000;
select name,salary from employee where salary not between 20000 and 30000; select * from employee where age = 73 or age = 81 or age = 28;
select * from employee where age in (73,81,28); select * from employee where post_comment is Null; #判断是否为空
select * from employee where post_comment is not Null; select * from employee where name like "jin%"; #模糊匹配 %代表任意多个字符，jin开头的不管后边是什么
select * from employee where name like "jin___"; ##___三个下划线代表3个任意字符
mysql> select id,name,age from employee where id > ;
+----+-----------+-----+
| id | name | age |
+----+-----------+-----+
| | 成龙 | |
| | 歪歪 | |
| | 丫丫 | |
| | 丁丁 | |
| | 星星 | |
| | 格格 | |
| | 张野 | |
| | 程咬金 | |
| | 程咬银 | |
| | 程咬铜 | |
| | 程咬铁 | |
+----+-----------+-----+
rows in set (0.13 sec) mysql> select name,post,salary from employee where post='teacher' and salary >
;
+------------+---------+------------+
| name | post | salary |
+------------+---------+------------+
| alex | teacher | 1000000.31 |
| wupeiqi | teacher | 8300.00 |
| jingliyang | teacher | 9000.00 |
| jinxin | teacher | 30000.00 |
| 成龙 | teacher | 10000.00 |
+------------+---------+------------+
rows in set (0.04 sec) mysql> select name,salary from employee where salary >= and salary <=; +-----------+----------+
| name | salary |
+-----------+----------+
| jinxin | 30000.00 |
| 程咬金 | 20000.00 |
+-----------+----------+
rows in set (0.00 sec) mysql> select name,salary from employee where salary between and ;
+-----------+----------+
| name | salary |
+-----------+----------+
| jinxin | 30000.00 |
| 程咬金 | 20000.00 |
+-----------+----------+
rows in set (0.07 sec) mysql> select name,salary from employee where salary < or salary > ;
+------------+------------+
| name | salary |
+------------+------------+
| egon | 7300.33 |
| alex | 1000000.31 |
| wupeiqi | 8300.00 |
| yuanhao | 3500.00 |
| liwenzhou | 2100.00 |
| jingliyang | 9000.00 |
| 成龙 | 10000.00 |
| 歪歪 | 3000.13 |
| 丫丫 | 2000.35 |
| 丁丁 | 1000.37 |
| 星星 | 3000.29 |
| 格格 | 4000.33 |
| 张野 | 10000.13 |
| 程咬银 | 19000.00 |
| 程咬铜 | 18000.00 |
| 程咬铁 | 17000.00 |
+------------+------------+
rows in set (0.01 sec) mysql> select name,salary from employee where salary not between and
;
+------------+------------+
| name | salary |
+------------+------------+
| egon | 7300.33 |
| alex | 1000000.31 |
| wupeiqi | 8300.00 |
| yuanhao | 3500.00 |
| liwenzhou | 2100.00 |
| jingliyang | 9000.00 |
| 成龙 | 10000.00 |
| 歪歪 | 3000.13 |
| 丫丫 | 2000.35 |
| 丁丁 | 1000.37 |
| 星星 | 3000.29 |
| 格格 | 4000.33 |
| 张野 | 10000.13 |
| 程咬银 | 19000.00 |
| 程咬铜 | 18000.00 |
| 程咬铁 | 17000.00 |
+------------+------------+
rows in set (0.00 sec) mysql> select * from employee where age = or age = or age = ;
+----+-----------+--------+-----+------------+-----------+--------------+----------+--------+-----------+
| id | name | sex | age | hire_date | post | post_comment | salary | office | depart_id |
+----+-----------+--------+-----+------------+-----------+--------------+----------+--------+-----------+
| 3 | wupeiqi | male | 81 | 2013-03-05 | teacher | NULL | 8300.00 | 401 | 1 |
| 4 | yuanhao | male | 73 | 2014-07-01 | teacher | NULL | 3500.00 | 401 | 1 |
| 5 | liwenzhou | male | 28 | 2012-11-01 | teacher | NULL | 2100.00 | 401 | 1 |
| 13 | 格格 | female | 28 | 2017-01-27 | sale | NULL | 4000.33 | 402 | 2 |
| 14 | 张野 | male | 28 | 2016-03-11 | operation | NULL | 10000.13 | 403 | 3 |
+----+-----------+--------+-----+------------+-----------+--------------+----------+--------+-----------+
rows in set (0.00 sec) mysql> select * from employee where post_comment is Null;
+----+------------+--------+-----+------------+-----------------------------------------+--------------+------------+--------+-----------+
| id | name | sex | age | hire_date | post | post_comment | salary | office | depart_id |
+----+------------+--------+-----+------------+-----------------------------------------+--------------+------------+--------+-----------+
| 1 | egon | male | 18 | 2017-03-01 | 老男孩驻沙河办事处外交大使 | NULL | 7300.33 | 401 | 1 |
| 2 | alex | male | 78 | 2015-03-02 | teacher | NULL | 1000000.31 | 401 | 1 |
| 3 | wupeiqi | male | 81 | 2013-03-05 | teacher | NULL | 8300.00 | 401 | 1 |
| 4 | yuanhao | male | 73 | 2014-07-01 | teacher | NULL | 3500.00 | 401 | 1 |
| 5 | liwenzhou | male | 28 | 2012-11-01 | teacher | NULL | 2100.00 | 401 | 1 |
| 6 | jingliyang | female | 18 | 2011-02-11 | teacher | NULL | 9000.00 | 401 | 1 |
| 7 | jinxin | male | 18 | 1900-03-01 | teacher | NULL | 30000.00 | 401 | 1 |
| 8 | 成龙 | male | 48 | 2010-11-11 | teacher | NULL | 10000.00 | 401 | 1 |
| 9 | 歪歪 | female | 48 | 2015-03-11 | sale | NULL | 3000.13 | 402 | 2 |
| 10 | 丫丫 | female | 38 | 2010-11-01 | sale | NULL | 2000.35 | 402 | 2 |
| 11 | 丁丁 | female | 18 | 2011-03-12 | sale | NULL | 1000.37 | 402 | 2 |
| 12 | 星星 | female | 18 | 2016-05-13 | sale | NULL | 3000.29 | 402 | 2 |
| 13 | 格格 | female | 28 | 2017-01-27 | sale | NULL | 4000.33 | 402 | 2 |
| 14 | 张野 | male | 28 | 2016-03-11 | operation | NULL | 10000.13 | 403 | 3 |
| 15 | 程咬金 | male | 18 | 1997-03-12 | operation | NULL | 20000.00 | 403 | 3 |
| 16 | 程咬银 | female | 18 | 2013-03-11 | operation | NULL | 19000.00 | 403 | 3 |
| 17 | 程咬铜 | male | 18 | 2015-04-11 | operation | NULL | 18000.00 | 403 | 3 |
| 18 | 程咬铁 | female | 18 | 2014-05-12 | operation | NULL | 17000.00 | 403 | 3 |
+----+------------+--------+-----+------------+-----------------------------------------+--------------+------------+--------+-----------+
rows in set (0.00 sec) mysql> select * from employee where name like "jin%"; ##模糊匹配，%代表任意字符，jin开头的不管后边是什么
+----+------------+--------+-----+------------+---------+--------------+----------+--------+-----------+
| id | name | sex | age | hire_date | post | post_comment | salary| office | depart_id |
+----+------------+--------+-----+------------+---------+--------------+----------+--------+-----------+
| | jingliyang | female | | -- | teacher | NULL | 9000.0 | | |
| | jinxin | male | | -- | teacher | NULL | 30000.0 | | |
+----+------------+--------+-----+------------+---------+--------------+----------+--------+-----------+
rows in set (0.09 sec) mysql> select * from employee where name like "jin___"; ##___三个下划线代表3个任意字符。
+----+--------+------+-----+------------+---------+--------------+----------+--------+-----------+
| id | name | sex | age | hire_date | post | post_comment | salary | office | depart_id |
+----+--------+------+-----+------------+---------+--------------+----------+--------+-----------+
| | jinxin | male | | -- | teacher | NULL | 30000.00 | | |
+----+--------+------+-----+------------+---------+--------------+----------+--------+-----------+
row in set (0.00 sec)
group by 分组查询 #group by分组 在where之后运行
分组就是按照相应字段进行归类，每后边那个字就是要分的字段
mysql> set global sql_mode="ONLY_FULL_GROUP_BY";
分组之后，只能取分组的字段，以及每个组 聚合的结果 select post from employee group by post;
单独使用GROUP BY关键字分组
SELECT post FROM employee GROUP BY post;
注意：我们按照post字段分组，那么select查询的字段只能是post，想要获取组内的其他相关信息，需要借助函数 GROUP BY关键字和GROUP_CONCAT()函数一起使用
SELECT post,GROUP_CONCAT(name) FROM employee GROUP BY post;#按照岗位分组，并查看组内成员名
SELECT post,GROUP_CONCAT(name) as emp_members FROM employee GROUP BY post; GROUP BY与聚合函数一起使用
select post,count(id) as count from employee group by post;#按照岗位分组，并查看每个组有多少人
#聚合函数 #以组为单位进行统计，不再考虑个人
max
min
avg
sum
count select post,count(id) as emp_count from employee group by post;##每个部门/职位有多少个员工；先确定你的表
select post,max(salary) as emp_max from employee group by post;
select post,min(salary) as emp_min from employee group by post;
select post,avg(salary) as emp_avg from employee group by post;
select post,sum(age) as emp_sum from employee group by post;
mysql> select * from employee group by post;
+----+--------+--------+-----+------------+-----------------------------------------+--------------+------------+--------+-----------+
| id | name | sex | age | hire_date | post | post_comment | salary | office | depart_id |
+----+--------+--------+-----+------------+-----------------------------------------+--------------+------------+--------+-----------+
| 14 | 张野 | male | 28 | 2016-03-11 | operation | NULL | 10000.13 | 403 | 3 |
| 9 | 歪歪 | female | 48 | 2015-03-11 | sale | NULL | 3000.13 | 402 | 2 |
| 2 | alex | male | 78 | 2015-03-02 | teacher | NULL | 1000000.31 | 401 | 1 |
| 1 | egon | male | 18 | 2017-03-01 | 老男孩驻沙河办事处外交大使 | NULL | 7300.33 | 401 | 1 |
+----+--------+--------+-----+------------+-----------------------------------------+--------------+------------+--------+-----------+
rows in set (0.08 sec)
#由于没有设置ONLY_FULL_GROUP_BY,于是也可以有结果，默认都是组内的第一条记录（就是按照post分组，如operation组内的第一条记录。），但其实这是没有意义的mysql> set global sql_mode="ONLY_FULL_GROUP_BY";
Query OK, rows affected (0.11 sec) ##设置成功一定要先退出，然后重新登录方可生效。然后你再select * 或者 select name就会报错了。 mysql> exit
Bye C:\Users\Administrator>mysql -uroot -p
Enter password:
Welcome to the MySQL monitor. Commands end with ; or \g.
Your MySQL connection id is
Server version: 5.6. MySQL Community Server (GPL)
Copyright (c) , , Oracle and/or its affiliates. All rights reserved.
Oracle is a registered trademark of Oracle Corporation and/or its
affiliates. Other names may be trademarks of their respective
owners.
Type 'help;' or '\h' for help. Type '\c' to clear the current input statement. mysql> use db5;
Database changed
mysql> select * from employee group by post;
ERROR (): 'db5.employee.id' isn't in GROUP BY
mysql> select post from employee group by post;
+-----------------------------------------+
| post |
+-----------------------------------------+
| operation |
| sale |
| teacher |
| 老男孩驻沙河办事处外交大使 |
+-----------------------------------------+
rows in set (0.00 sec) mysql> select post,count(id) as emp_count from employee group by post; #查询组内的id数
+-----------------------------------------+-----------+
| post | emp_count |
+-----------------------------------------+-----------+
| operation | |
| sale | |
| teacher | |
| 老男孩驻沙河办事处外交大使 | |
+-----------------------------------------+-----------+
rows in set (0.06 sec)
强调：如果我们用unique的字段作为分组的依据，则每一条记录自成一组，这种分组没有意义
多条记录之间的某个字段值相同，该字段通常用来作为分组的依据
#没有group by则默认整体算作一组
select max(salary) from employee; #取所有员工的最高工资 #group_concat(name) 职位包含的所有员工成员的名字
select post,group_concat(name) from employee group by post;
mysql> select max(salary) from employee;
+-------------+
| max(salary) |
+-------------+
| 1000000.31 |
+-------------+
row in set (0.07 sec) mysql> select post,group_concat(name) from employee group by post; ##也可以查询组内成员的性别group_concat(sex)；
+-----------------------------------------+-------------------------------------
| post | group_concat(name)
+-----------------------------------------+-------------------------------------
| operation | 程咬铁,程咬铜,程咬银,程咬金,张野
|
| sale | 格格,星星,丁丁,丫丫,歪歪
|
| teacher | 成龙,jinxin,jingliyang,liwenzhou,yuanhao,wupeiqi,alex |
| 老男孩驻沙河办事处外交大使 | egon
|
+-----------------------------------------+-------------------------------------
rows in set (0.01 sec)
#练习：
. 查询岗位名以及岗位包含的所有员工名字 #先确定你查的是哪张表，有没有过滤条件where，有没有分组分类的；
. 先取出年龄在50以上的然后再 查询岗位名以及各岗位内包含的员工个数
. 查询公司内男员工和女员工的个数
. 查询岗位名以及各岗位的平均薪资
. 查询岗位名以及各岗位的最高薪资
. 查询岗位名以及各岗位的最低薪资
. 查询男员工与男员工的平均薪资，女员工与女员工的平均薪资
select post,group_concat(name) from employee group by post; select post,count(id) from employee where age > 50 group by post; select sex,count(id) from employee group by sex; select sex,avg(salary) from employee group by sex;
mysql> select post,group_concat(name) from employee group by post;
+-----------------------------------------+------------------------------------
| post | group_concat(name)
+-----------------------------------------+------------------------------------
| operation | 程咬铁,程咬铜,程咬银,程咬金,张野
|
| sale | 格格,星星,丁丁,丫丫,歪歪
|
| teacher | 成龙,jinxin,jingliyang,liwenzhou,yunhao,wupeiqi,alex |
| 老男孩驻沙河办事处外交大使 | egon
|
+-----------------------------------------+------------------------------------
rows in set (0.00 sec) mysql> select post,count(id) from employee where age > group by post;
+---------+-----------+
| post | count(id) |
+---------+-----------+
| teacher | |
+---------+-----------+
row in set (0.00 sec) mysql> select sex,count(id) from employee group by sex;
+--------+-----------+
| sex | count(id) |
+--------+-----------+
| male | |
| female | |
+--------+-----------+
rows in set (0.00 sec) mysql> select sex,avg(salary) from employee group by sex;
+--------+---------------+
| sex | avg(salary) |
+--------+---------------+
| male | 110920.077000 |
| female | 7250.183750 |
+--------+---------------+
rows in set (0.00 sec)
mysql> select sex,max(age) from employee group by sex;
+--------+----------+
| sex | max(age) |
+--------+----------+
| male | 81 |
| female | 48 |
+--------+----------+
2 rows in set (0.06 sec)
#having 过滤条件 在分组之后进行；where在分组之前 （过滤的是分组组内的成员）
例如：
. 查询各岗位内包含的员工个数小于2的岗位名、岗位内包含员工名字、个数 #聚合出员工个数
. 查询各岗位平均薪资大于10000的岗位名、平均工资
. 查询各岗位平均薪资大于10000且小于20000的岗位名、平均工资 and avg(salary) < 20000;
select post,group_concat(name),count(id) from employee group by post; select post,group_concat(name),count(id) from employee group by post having count(id) < 2; select post,avg(salary) from employee group by post having avg(salary) > 10000;
mysql> select post,group_concat(name), count(id) from employee group by post;
+-----------------------------------------+-------------------------------------
| post |count(id) | | group_concat(name)
+-----------------------------------------+-------------------------------------
| operation | 5 | | 程咬铁,程咬铜,程咬银,程咬金,张野 | sale | 5 | | 格格,星星,丁丁,丫丫,歪歪 | teacher | 7 | | 成龙,jinxin,jingliyang,liwenzhou,yuanhao,wupeiqi,alex
| 老男孩驻沙河办事处外交大使| 1 | | egon
+-----------------------------------------+-------------------------------------
rows in set (0.00 sec) mysql> select post,group_concat(name),count(id) from employee group by post having count(id) < ;
+-----------------------------------------+--------------------+-----------+
| post | group_concat(name) | count(id) |
+-----------------------------------------+--------------------+-----------+
| 老男孩驻沙河办事处外交大使 | egon | |
+-----------------------------------------+--------------------+-----------+
row in set (0.01 sec) mysql> select post,avg(salary) from employee group by post having avg(salary) >
-> \c
mysql> select post, avg(salary) from employee group by post having avg(salary) > and avg(salary) < ;
+-----------+--------------+
| post | avg(salary) |
+-----------+--------------+
| operation | 16800.026000 |
+-----------+--------------+
row in set (0.00 sec)
#order by 默认就是升序
select * from employee order by age asc; #升序，不加asc也可以，默认 从低到高
select * from employee order by age desc; #降序 从高到低 select * from employee order by age asc,id desc; #先按照age升序排，如果age相同则按照id降序排； 聚合函数不能用在where内；分完组之后才能用聚合函数，having可以用；select max(salary) from employee 这里边运行max的时候就已经分组了； 先找表，再where再分组，...最后才打印select你想打印的内容
select distinct post,count(id) as emp_count from employee
where salary > 1000
group by post
having count(id) > 1 #在这个位置不能用emp_count>1，因为运行having之前还没运行distinct这个字段呢
order by emp_count desc #可以用count(id)，它是在分组之后干的；emp_count也可以用，因为order by 是在distinct后边运行；
;
mysql> select * from employee order by age asc, id desc; #在age asc 的组内进行id排序。
+----+------------+--------+-----+------------+-----------------------------------------+--------------+------------+--------+-----------+
| id | name | sex | age | hire_date | post | post_comment | salary | office | depart_id |
+----+------------+--------+-----+------------+-----------------------------------------+--------------+------------+--------+-----------+
| 18 | 程咬铁 | female | 18 | 2014-05-12 | operation | NULL | 17000.00 | 403 | 3 |
| 17 | 程咬铜 | male | 18 | 2015-04-11 | operation | NULL | 18000.00 | 403 | 3 |
| 16 | 程咬银 | female | 18 | 2013-03-11 | operation | NULL | 19000.00 | 403 | 3 |
| 15 | 程咬金 | male | 18 | 1997-03-12 | operation | NULL | 20000.00 | 403 | 3 |
| 12 | 星星 | female | 18 | 2016-05-13 | sale | NULL | 3000.29 | 402 | 2 |
| 11 | 丁丁 | female | 18 | 2011-03-12 | sale | NULL | 1000.37 | 402 | 2 |
| 7 | jinxin | male | 18 | 1900-03-01 | teacher | NULL | 30000.00 | 401 | 1 |
| 6 | jingliyang | female | 18 | 2011-02-11 | teacher | NULL | 9000.00 | 401 | 1 |
| 1 | egon | male | 18 | 2017-03-01 | 老男孩驻沙河办事处外交大使 | NULL | 7300.33 | 401 | 1 |
| 14 | 张野 | male | 28 | 2016-03-11 | operation | NULL | 10000.13 | 403 | 3 |
| 13 | 格格 | female | 28 | 2017-01-27 | sale | NULL | 4000.33 | 402 | 2 |
| 5 | liwenzhou | male | 28 | 2012-11-01 | teacher | NULL | 2100.00 | 401 | 1 |
| 10 | 丫丫 | female | 38 | 2010-11-01 | sale | NULL | 2000.35 | 402 | 2 |
| 9 | 歪歪 | female | 48 | 2015-03-11 | sale | NULL | 3000.13 | 402 | 2 |
| 8 | 成龙 | male | 48 | 2010-11-11 | teacher | NULL | 10000.00 | 401 | 1 |
| 4 | yuanhao | male | 73 | 2014-07-01 | teacher | NULL | 3500.00 | 401 | 1 |
| 2 | alex | male | 78 | 2015-03-02 | teacher | NULL | 1000000.31 | 401 | 1 |
| 3 | wupeiqi | male | 81 | 2013-03-05 | teacher | NULL | 8300.00 | 401 | 1 |
+----+------------+--------+-----+------------+-----------------------------------------+--------------+------------+--------+-----------+
18 rows in set (0.00 sec)
mysql> select distinct post, count(id) as emp_count from employee
-> where salary >
-> group by post
-> having count(id) >
-> order by emp_count desc;
+-----------+-----------+
| post | emp_count |
+-----------+-----------+
| teacher | |
| sale | |
| operation | |
+-----------+-----------+
rows in set (0.00 sec)
#limit限制打印条数
select * from employee limit 3;
select * from employee order by salary desc limit 1; #找工资最高的那个人的详细信息 select * from employee limit 0,5; #从0开始往后再取5个；基本的分页功能
select * from employee limit 5,5;
select * from employee limit 10,5;
select * from employee limit 15,5;
mysql> select * from employee limit 3;
+----+---------+------+-----+------------+-----------------------------------------+--------------+------------+--------+-----------+
| id | name | sex | age | hire_date | post | post_comment | salary | office | depart_id |
+----+---------+------+-----+------------+-----------------------------------------+--------------+------------+--------+-----------+
| 1 | egon | male | 18 | 2017-03-01 | 老男孩驻沙河办事处外交大使 | NULL | 7300.33 | 401 | 1 |
| 2 | alex | male | 78 | 2015-03-02 | teacher | NULL | 1000000.31 | 401 | 1 |
| 3 | wupeiqi | male | 81 | 2013-03-05 | teacher | NULL | 8300.00 | 401 | 1 |
+----+---------+------+-----+------------+-----------------------------------------+--------------+------------+--------+-----------+
3 rows in set (0.00 sec) mysql> select * from employee order by salary desc limit 1;
+----+------+------+-----+------------+---------+--------------+------------+--------+-----------+
| id | name | sex | age | hire_date | post | post_comment | salary | office | depart_id |
+----+------+------+-----+------------+---------+--------------+------------+--------+-----------+
| 2 | alex | male | 78 | 2015-03-02 | teacher | NULL | 1000000.31 | 401 | 1 |
+----+------+------+-----+------------+---------+--------------+------------+--------+-----------+
1 row in set (0.00 sec) mysql> select * from employee limit 0,5;
+----+-----------+------+-----+------------+-----------------------------------------+--------------+------------+--------+-----------+
| id | name | sex | age | hire_date | post | post_comment | salary | office | depart_id |
+----+-----------+------+-----+------------+-----------------------------------------+--------------+------------+--------+-----------+
| 1 | egon | male | 18 | 2017-03-01 | 老男孩驻沙河办事处外交大使 | NULL | 7300.33 | 401 | 1 |
| 2 | alex | male | 78 | 2015-03-02 | teacher | NULL | 1000000.31 | 401 | 1 |
| 3 | wupeiqi | male | 81 | 2013-03-05 | teacher | NULL | 8300.00 | 401 | 1 |
| 4 | yuanhao | male | 73 | 2014-07-01 | teacher | NULL | 3500.00 | 401 | 1 |
| 5 | liwenzhou | male | 28 | 2012-11-01 | teacher | NULL | 2100.00 | 401 | 1 |
+----+-----------+------+-----+------------+-----------------------------------------+--------------+------------+--------+-----------+
5 rows in set (0.00 sec)
#总结：
语法顺序：
select distinct 字段1,字段2,字段3 from 库.表
where 条件
group by 分组条件
having 过滤
order by 排序字段
limit n; 执行顺序： def from(db,table):
f=open(r'%s\%s' %(db,table)) #打开文件
return f #返回文件对象 def where(condition,f):
for line in f:
if condition:
yield line #满足条件再返回，不停地返回 def group(lines): #分组
pass def having(group_res): #分组，拿到分组的结果
pass def distinct(having_res): #拿到having_res的结果
pass def order(distinct_res): #拿到distinct_res的结果
pass def limit(order_res) #
pass def select():
f=from('db1','t1') #找表
lines=where('id>3',f)
group_res=group(lines)
having_res=having(group_res)
distinct_res=distinct(having_res)
order_res=order(distinct_res)
res=limit(order_res)
print(res)
return res #返回值 #正则表达式 查询
select * from employee where name like 'jin%';
select * from employee where name regexp '^jin'; #以什么开头^
select * from employee where name regexp '^jin.*(g|n)$'; # .*()以什么结尾 ，以g或者n结尾
mysql> select * from employee where name regexp '^jin';
+----+------------+--------+-----+------------+---------+--------------+----------+--------+-----------+
| id | name | sex | age | hire_date | post | post_comment | salary| office | depart_id |
+----+------------+--------+-----+------------+---------+--------------+----------+--------+-----------+
| | jingliyang | female | | -- | teacher | NULL | 9000.0 | | |
| | jinxin | male | | -- | teacher | NULL | 30000.0 | | |
+----+------------+--------+-----+------------+---------+--------------+----------+--------+-----------+
rows in set (0.07 sec) mysql> select * from employee where name regexp '^jin.*(g|n)$';
+----+------------+--------+-----+------------+---------+--------------+----------+--------+-----------+
| id | name | sex | age | hire_date | post | post_comment | salary| office | depart_id |
+----+------------+--------+-----+------------+---------+--------------+----------+--------+-----------+
| | jingliyang | female | | -- | teacher | NULL | 9000.0 | | |
| | jinxin | male | | -- | teacher | NULL | 30000.0 | | |
+----+------------+--------+-----+------------+---------+--------------+----------+--------+-----------+
rows in set (0.00 sec)
1.3 多表查询
把有关系的表连接合到一起； department和employee表是多对一的关系。
内连接：只取两张表的共同部分
select * from employee inner join department on employee.dep_id = department.id ; 左连接:在内连接的基础上保留左表的记录
select * from employee left join department on employee.dep_id = department.id ; 右连接：在内连接的基础上保留右表的记录
select * from employee right join department on employee.dep_id = department.id ; 全外连接：在内连接的基础上保留左右两表没有对应关系的记录
select * from employee full join department on employee.dep_id = department.id ; #mysql不支持full join select * from employee left join department on employee.dep_id = department.id
union
select * from employee right join department on employee.dep_id = department.id ;
笛卡尔积；在笛卡尔积的基础之中对表进行筛选，where，这就是连接；不要用where干，它是过滤的，有专门的方法
mysql> create database db6;
Query OK, row affected (0.01 sec) mysql> use db6;
Database changed
mysql> create table department(
-> id int,
-> name varchar()
-> );
Query OK, rows affected (0.78 sec) mysql> create table employee(
-> id int primary key auto_increment,
-> name varchar(),
-> sex enum('male','female') not null default 'male',
-> age int,
-> dep_id int
-> );
Query OK, rows affected (1.05 sec) mysql> insert into department values
-> (,'技术'),
-> (,'人力资源'),
-> (,'销售'),
-> (,'运营');
Query OK, rows affected (0.19 sec)
Records: Duplicates: Warnings: mysql> insert into employee(name,sex,age,dep_id) values
-> ('egon','male',,),
-> ('alex','female',,),
-> ('wupeiqi','male',,),
-> ('yuanhao','female',,),
-> ('liwenzhou','male',,),
-> ('jingliyang','female',,)
-> ;
Query OK, rows affected (0.15 sec)
Records: Duplicates: Warnings:
mysql> select * from department;
+------+--------------+
| id | name |
+------+--------------+
| | 技术 |
| | 人力资源 |
| | 销售 |
| 203 | 运营 |
+------+--------------+
rows in set (0.00 sec) mysql> select * from employee;
+----+------------+--------+------+--------+
| id | name | sex | age | dep_id |
+----+------------+--------+------+--------+
| | egon | male | | |
| | alex | female | | |
| | wupeiqi | male | | |
| | yuanhao | female | | |
| | liwenzhou | male | | |
| | jingliyang | female | | |
+----+------------+--------+------+--------+
rows in set (0.00 sec) mysql> select * from employee,department;
+----+------------+--------+------+--------+------+--------------+
| id | name | sex | age | dep_id | id | name |
+----+------------+--------+------+--------+------+--------------+
| | egon | male | | | | 技术 |
| | egon | male | | | | 人力资源 |
| | egon | male | | | | 销售 |
| | egon | male | | | | 运营 |
| | alex | female | | | | 技术 |
| | alex | female | | | | 人力资源 |
| | alex | female | | | | 销售 |
| | alex | female | | | | 运营 |
| | wupeiqi | male | | | | 技术 |
| | wupeiqi | male | | | | 人力资源 |
| | wupeiqi | male | | | | 销售 |
| | wupeiqi | male | | | | 运营 |
| | yuanhao | female | | | | 技术 |
| | yuanhao | female | | | | 人力资源 |
| | yuanhao | female | | | | 销售 |
| | yuanhao | female | | | | 运营 |
| | liwenzhou | male | | | | 技术 |
| | liwenzhou | male | | | | 人力资源 |
| | liwenzhou | male | | | | 销售 |
| | liwenzhou | male | | | | 运营 |
| | jingliyang | female | | | | 技术 |
| | jingliyang | female | | | | 人力资源 |
| | jingliyang | female | | | | 销售 |
| | jingliyang | female | | | | 运营 |
+----+------------+--------+------+--------+------+--------------+
rows in set (0.07 sec) mysql> select * from employee inner join department on employee.dep_id = department.id ; #共同的部分是200/201/202
+----+-----------+--------+------+--------+------+--------------+
| id | name | sex | age | dep_id | id | name |
+----+-----------+--------+------+--------+------+--------------+
| | egon | male | | | | 技术 |
| | alex | female | | | | 人力资源 |
| | wupeiqi | male | | | | 人力资源 |
| | yuanhao | female | | | | 销售 |
| | liwenzhou | male | | | | 技术 |
+----+-----------+--------+------+--------+------+--------------+
rows in set (0.00 sec) mysql> select * from employee left join department on employee.dep_id = department.id ; #左边employee独有的204
+----+------------+--------+------+--------+------+--------------+
| id | name | sex | age | dep_id | id | name |
+----+------------+--------+------+--------+------+--------------+
| | egon | male | | | | 技术 |
| | liwenzhou | male | | | | 技术 |
| | alex | female | | | | 人力资源 |
| | wupeiqi | male | | | | 人力资源 |
| | yuanhao | female | | | | 销售 |
| | jingliyang | female | | 204 | NULL | NULL |
+----+------------+--------+------+--------+------+--------------+
rows in set (0.00 sec) mysql> select * from employee right join department on employee.dep_id = department.id ; #右边department独有的203
+------+-----------+--------+------+--------+------+--------------+
| id | name | sex | age | dep_id | id | name |
+------+-----------+--------+------+--------+------+--------------+
| | egon | male | | | | 技术 |
| | alex | female | | | | 人力资源 |
| | wupeiqi | male | | | | 人力资源 |
| | yuanhao | female | | | | 销售 |
| | liwenzhou | male | | | | 技术 |
| NULL | NULL | NULL | NULL | NULL | 203 | 运营 |
+------+-----------+--------+------+--------+------+--------------+
rows in set (0.00 sec) mysql> select * from employee left join department on employee.dep_id = department.id
-> union
-> select * from employee right join department on employee.dep_id = department.id;
+------+------------+--------+------+--------+------+--------------+
| id | name | sex | age | dep_id | id | name |
+------+------------+--------+------+--------+------+--------------+
| | egon | male | | | | 技术 |
| | liwenzhou | male | | | | 技术 |
| | alex | female | | | | 人力资源 |
| | wupeiqi | male | | | | 人力资源 |
| | yuanhao | female | | | | 销售 |
| | jingliyang | female | | | NULL | NULL |
| NULL | NULL | NULL | NULL | NULL | | 运营 |
+------+------------+--------+------+--------+------+--------------+
rows in set (0.11 sec)
#查询平均年龄大于30岁的部门名
select * from employee inner join department on employee.dep_id = department.id;
select department.name,avg(age) from employee inner join department on employee.dep_id = department.id
group by department.name
having avg(age) > 30;
mysql> desc employee;
+--------+-----------------------+------+-----+---------+----------------+
| Field | Type | Null | Key | Default | Extra |
+--------+-----------------------+------+-----+---------+----------------+
| id | int() | NO | PRI | NULL | auto_increment |
| name | varchar() | YES | | NULL | |
| sex | enum('male','female') | NO | | male | |
| age | int() | YES | | NULL | |
| dep_id | int() | YES | | NULL | |
+--------+-----------------------+------+-----+---------+----------------+
rows in set (0.01 sec) mysql> desc department;
+-------+-------------+------+-----+---------+-------+
| Field | Type | Null | Key | Default | Extra |
+-------+-------------+------+-----+---------+-------+
| id | int() | YES | | NULL | |
| name | varchar() | YES | | NULL | |
+-------+-------------+------+-----+---------+-------+
rows in set (0.01 sec) mysql> select department.name,avg(age) from employee inner join department on employee.dep_id = depa
rtment.id;
ERROR (): Mixing of GROUP columns (MIN(),MAX(),COUNT(),...) with no GROUP columns is illeg
al if there is no GROUP BY clause
mysql> select * from employee inner join department on employee.dep_id = department.id;
+----+-----------+--------+------+--------+------+--------------+
| id | name | sex | age | dep_id | id | name |
+----+-----------+--------+------+--------+------+--------------+
| | egon | male | | | | 技术 |
| | alex | female | | | | 人力资源 |
| | wupeiqi | male | | | | 人力资源 |
| | yuanhao | female | | | | 销售 |
| | liwenzhou | male | | | | 技术 |
+----+-----------+--------+------+--------+------+--------------+
rows in set (0.00 sec) mysql> select department.name,avg(age) from employee inner join department on employee.dep_id = department.id
-> group by department.name
-> having avg(age) > 30;
+--------------+----------+
| name | avg(age) |
+--------------+----------+
| 人力资源 | 43.0000 |
+--------------+----------+
row in set (0.00 sec)
SELECT语句关键字执行优先级
http://www.cnblogs.com/linhaifeng/articles/7372774.html
子查询
http://www.cnblogs.com/linhaifeng/articles/7267596.html
#：子查询是将一个查询语句嵌套在另一个查询语句中。
#：内层查询语句的查询结果，可以为外层查询语句提供查询条件。
#：子查询中可以包含：IN、NOT IN、ANY、ALL、EXISTS 和 NOT EXISTS等关键字
#：还可以包含比较运算符：= 、 !=、> 、<等
1、带IN关键字的子查询
查询平均年龄在25岁以上的部门名
方法一：
select department.name,avg(age) from employee inner join department on employee.dep_id = department.id
-> group by department.name
-> having avg(age) > 25;
方法二：
select name from department where id in
-> (select dep_id from employee
-> group by dep_id
-> having avg(age) > 25);
作为子查询-->> select dep_id from employee
group by dep_id
having avg(age) > 25;
mysql> select * from employee;
+----+------------+--------+------+--------+
| id | name | sex | age | dep_id |
+----+------------+--------+------+--------+
| | egon | male | | |
| | alex | female | | |
| | wupeiqi | male | | |
| | yuanhao | female | | |
| | liwenzhou | male | | |
| | jingliyang | female | | |
+----+------------+--------+------+--------+
rows in set (0.00 sec) mysql> select dep_id from employee
-> group by dep_id
-> having avg(age) > ;
+--------+
| dep_id |
+--------+
| |
| |
+--------+
rows in set (0.00 sec) mysql> select * from department;
+------+--------------+
| id | name |
+------+--------------+
| | 技术 |
| | 人力资源 |
| | 销售 |
| | 运营 |
+------+--------------+
rows in set (0.00 sec) mysql> select name from department where id in
-> (select dep_id from employee
-> group by dep_id
-> having avg(age) > );
+--------------+
| name |
+--------------+
| 人力资源 |
| 销售 |
+--------------+
rows in set (0.11 sec)
查看技术部员工姓名 # 涉及两种表
方法一：（使用join，不用分组）
select employee.name from department inner join employee on department.id=employee.dep_id
where department.name = '技术' ;
方法二：
select * from employee where dep_id = ( select employee.name from employee where dep_id = (
select id from department where name = "技术"); select id from department where name = '技术');
查看不足1人（not >=1）的部门名
方法一：（使用left join ，注意不能使用 where dep_id not in employee ; 这样语法是错误的）
select department.name from department left join employee on employee.dep_id = department.id
where dep_id is nul l ;
方法二：
select name from department where id not in (
select distinct dep_id from employee) ;
mysql> select id from department where name = "技术";
+------+
| id |
+------+
| |
+------+
row in set (0.00 sec) mysql> select * from employee where dep_id = (
-> select id from department where name = "技术");
+----+-----------+------+------+--------+
| id | name | sex | age | dep_id |
+----+-----------+------+------+--------+
| | egon | male | | |
| | liwenzhou | male | | |
+----+-----------+------+------+--------+
rows in set (0.00 sec) mysql> select name from employee where dep_id = (
-> select id from department where name = "技术");
+-----------+
| name |
+-----------+
| egon |
| liwenzhou |
+-----------+
rows in set (0.00 sec) mysql>
mysql> select * from employee;
+----+------------+--------+------+--------+
| id | name | sex | age | dep_id |
+----+------------+--------+------+--------+
| | egon | male | | |
| | alex | female | | |
| | wupeiqi | male | | |
| | yuanhao | female | | |
| | liwenzhou | male | | |
| | jingliyang | female | | |
+----+------------+--------+------+--------+
rows in set (0.00 sec) mysql> select dep_id from employee;
+--------+
| dep_id |
+--------+
| |
| |
| |
| |
| |
| |
+--------+
rows in set (0.00 sec) mysql> select distinct dep_id from employee;
+--------+
| dep_id |
+--------+
| |
| |
| |
| |
+--------+
rows in set (0.00 sec) mysql> select name from department where id not in (
-> select distinct dep_id from employee);
+--------+
| name |
+--------+
| 运营 |
+--------+
row in set (0.00 sec) mysql> select * from employee;
+----+------------+--------+------+--------+
| id | name | sex | age | dep_id |
+----+------------+--------+------+--------+
| | egon | male | | |
| | alex | female | | |
| | wupeiqi | male | | |
| | yuanhao | female | | |
| | liwenzhou | male | | |
| | jingliyang | female | | |
+----+------------+--------+------+--------+
rows in set (0.00 sec) mysql> select * from department;
+------+--------------+
| id | name |
+------+--------------+
| | 技术 |
| | 人力资源 |
| | 销售 |
| | 运营 |
+------+--------------+
rows in set (0.00 sec)
2、带比较运算符的子查询
查询大于所有人平均年龄的员工名与年龄 #先拿到所有人的平均年龄，然后把它作为条件
select name,age from employee where age > (select avg(age) from employee);
mysql> select avg(age) from employee;
+----------+
| avg(age) |
+----------+
| 28.0000 |
+----------+
row in set (0.06 sec) mysql> select name,age from employee where age > (select avg(age) from employee);
+---------+------+
| name | age |
+---------+------+
| alex | |
| wupeiqi | |
+---------+------+
rows in set (0.00 sec)
3、带EXISTS关键字的子查询 #针对某一个子查询问一问它有没有结果，有就为真了；
条件成立就拿到了
select * from employee
where EXISTS
(select id from department where name = "技术");
mysql> select * from employee
-> where EXISTS
-> (select id from department where name = "技术");
+----+------------+--------+------+--------+
| id | name | sex | age | dep_id |
+----+------------+--------+------+--------+
| | egon | male | | |
| | alex | female | | |
| | wupeiqi | male | | |
| | yuanhao | female | | |
| | liwenzhou | male | | |
| | jingliyang | female | | |
+----+------------+--------+------+--------+
rows in set (0.00 sec) ->
-> \c mysql> select * from employee
-> where EXISTS
-> (select id from department where name = "IT");
Empty set (0.00 sec)
把在内存中虚拟表留下来以便你查询用，把查询表起个名字当做一个表来用；
mysql> select id,name,sex from employee;
+----+------------+--------+
| id | name | sex |
+----+------------+--------+
| | egon | male |
| | alex | female |
| | wupeiqi | male |
| | yuanhao | female |
| | liwenzhou | male |
| | jingliyang | female |
+----+------------+--------+
rows in set (0.00 sec) mysql> select * from
-> (select id,name,sex from employee)as t1;
+----+------------+--------+
| id | name | sex |
+----+------------+--------+
| | egon | male |
| | alex | female |
| | wupeiqi | male |
| | yuanhao | female |
| | liwenzhou | male |
| | jingliyang | female |
+----+------------+--------+
rows in set (0.09 sec)
#统计每个（分组，得到聚合的结果）部门最新（时间最大的一个）入职的员工
select post ,max(hire_date) from employee group by post ;
得到的新表和原表连接到一起了
mysql> use db5;
Database changed
mysql> show tables;
+---------------+
| Tables_in_db5 |
+---------------+
| customer |
| employee |
| student |
+---------------+
rows in set (0.10 sec) mysql> select * from employee;
+----+------------+--------+-----+------------+-----------------------------------------+--------------+------------+--------+-----------+
| id | name | sex | age | hire_date | post | post_comment | salary | office | depart_id |
+----+------------+--------+-----+------------+-----------------------------------------+--------------+------------+--------+-----------+
| | egon | male | | -- | 老男孩驻沙河办事处外交大使 | NULL | 7300.33 | | |
| | alex | male | | -- | teacher | NULL | 1000000.31 | | |
| | wupeiqi | male | | -- | teacher | NULL | 8300.00 | | |
| | yuanhao | male | | -- | teacher | NULL | 3500.00 | | |
| | liwenzhou | male | | -- | teacher | NULL | 2100.00 | | |
| | jingliyang | female | | -- | teacher | NULL | 9000.00 | | |
| | jinxin | male | | -- | teacher | NULL | 30000.00 | | |
| | 成龙 | male | | -- | teacher | NULL | 10000.00 | | |
| | 歪歪 | female | | -- | sale | NULL | 3000.13 | | |
| | 丫丫 | female | | -- | sale | NULL | 2000.35 | | |
| | 丁丁 | female | | -- | sale | NULL | 1000.37 | | |
| | 星星 | female | | -- | sale | NULL | 3000.29 | | |
| | 格格 | female | | -- | sale | NULL | 4000.33 | | |
| | 张野 | male | | -- | operation | NULL | 10000.13 | | |
| | 程咬金 | male | | -- | operation | NULL | 20000.00 | | |
| | 程咬银 | female | | -- | operation | NULL | 19000.00 | | |
| | 程咬铜 | male | | -- | operation | NULL | 18000.00 | | |
| | 程咬铁 | female | | -- | operation | NULL | 17000.00 | | |
+----+------------+--------+-----+------------+-----------------------------------------+--------------+------------+--------+-----------+
rows in set (0.00 sec) mysql> select post ,max(hire_date) from employee group by post;
+-----------------------------------------+----------------+
| post | max(hire_date) |
+-----------------------------------------+----------------+
| operation | -- |
| sale | -- |
| teacher | -- |
| 老男孩驻沙河办事处外交大使 | -- |
+-----------------------------------------+----------------+
rows in set (0.06 sec) mysql> select * from employee as t1
-> inner join
-> (select post ,max(hire_date) from employee group by post) as t2
-> on t1.post = t2.post;
+----+------------+--------+-----+------------+-----------------------------------------+--------------+------------+--------+-----------+-----------------------------------------+----------------+
| id | name | sex | age | hire_date | post | post_comment | salary | office | depart_id | post | max(hire_date) |
+----+------------+--------+-----+------------+-----------------------------------------+--------------+------------+--------+-----------+-----------------------------------------+----------------+
| | egon | male | | -- | 老男孩驻沙河办事处外交大使 | NULL | 7300.33 | | | 老男孩驻沙河办事处外交大使 | -- |
| | alex | male | | -- | teacher | NULL | 1000000.31 | | | teacher | -- |
| | wupeiqi | male | | -- | teacher | NULL | 8300.00 | | | teacher | -- |
| | yuanhao | male | | -- | teacher | NULL | 3500.00 | | | teacher | -- |
| | liwenzhou | male | | -- | teacher | NULL | 2100.00 | | | teacher | -- |
| | jingliyang | female | | -- | teacher | NULL | 9000.00 | | | teacher | -- |
| | jinxin | male | | -- | teacher | NULL | 30000.00 | | | teacher | -- |
| | 成龙 | male | | -- | teacher | NULL | 10000.00 | | | teacher | -- |
| | 歪歪 | female | | -- | sale | NULL | 3000.13 | | | sale | -- |
| | 丫丫 | female | | -- | sale | NULL | 2000.35 | | | sale | -- |
| | 丁丁 | female | | -- | sale | NULL | 1000.37 | | | sale | -- |
| | 星星 | female | | -- | sale | NULL | 3000.29 | | | sale | -- |
| | 格格 | female | | -- | sale | NULL | 4000.33 | | | sale | -- |
| | 张野 | male | | -- | operation | NULL | 10000.13 | | | operation | -- |
| | 程咬金 | male | | -- | operation | NULL | 20000.00 | | | operation | -- |
| | 程咬银 | female | | -- | operation | NULL | 19000.00 | | | operation | -- |
| | 程咬铜 | male | | -- | operation | NULL | 18000.00 | | | operation | -- |
| | 程咬铁 | female | | -- | operation | NULL | 17000.00 | | | operation | -- |
+----+------------+--------+-----+------------+-----------------------------------------+--------------+------------+--------+-----------+-----------------------------------------+----------------+
rows in set (0.00 sec) mysql> select post ,max(hire_date) from employee group by post;
+-----------------------------------------+----------------+
| post | max(hire_date) |
+-----------------------------------------+----------------+
| operation | -- |
| sale | -- |
| teacher | -- |
| 老男孩驻沙河办事处外交大使 | -- |
+-----------------------------------------+----------------+
rows in set (0.04 sec) mysql> select * from employee as t1
-> inner join
-> (select post ,max(hire_date) as max_hire_date from employee group by post) as t2
-> on t1.post = t2.post
-> where t1.hire_date = t2.max_hire_date;
+----+--------+--------+-----+------------+-----------------------------------------+--------------+------------+--------+-----------+-----------------------------------------+---------------+
| id | name | sex | age | hire_date | post | post_comment | salary | office | depart_id | post | max_hire_date |
+----+--------+--------+-----+------------+-----------------------------------------+--------------+------------+--------+-----------+-----------------------------------------+---------------+
| | egon | male | | -- | 老男孩驻沙河办事处外交大使 | NULL | 7300.33 | | | 老男孩驻沙河办事处外交大使 | -- |
| | alex | male | | -- | teacher | NULL | 1000000.31 | | | teacher | -- |
| | 格格 | female | | -- | sale | NULL | 4000.33 | | | sale | -- |
| | 张野 | male | | -- | operation | NULL | 10000.13 | | | operation | -- |
+----+--------+--------+-----+------------+-----------------------------------------+--------------+------------+--------+-----------+-----------------------------------------+---------------+
rows in set (0.07 sec)
2. 权限管理
root@%（表示这个root这个账号允许其他机器连接） 和 root@localhost（允许mysql安装的机器连接），是因mysql对安全性的重视。这样的区分，即使别人盗取了数据库的账号和密码，从他的机器连接到mysql的服务端，我们还是可以控制他的操作权限，也就有了更高的安全性。
权限管理
、创建账号
# 本地账号
create user 'egon1'@'localhost' identified by ''; # mysql -uegon1 -p123
# 远程帐号 #前提是31.10能拼通我服务端的ip这才有意义
create user 'egon2'@'192.168.31.10' identified by ''; # mysql -uegon2 -p123 -h 指定的是服务端ip ##运行egon2在这台机器之上登录；‘192.168.31.10’是客户端的ip地址
create user 'egon3'@'192.168.31.%' identified by ''; # mysql -uegon3 -p123 -h 服务端ip #表示egon3用户能在31这段网中任意登录
create user 'egon3'@'%' identified by ''; # mysql -uegon3 -p123 -h 服务端ip #所有的客户端ip都能登录，只要你能拼通服务端。 2、授权 这几张表对权限的控制是依次降低的
user:*.* # *.* 所有库下边所有的表 只要user一放权，下面所有的都可以用了
db:db1.* #具体写哪个库，只对某个库有查询权限，库下边所有的表
tables_priv:db1.t1 #表级别的权限
columns_priv:id,name #针对某个字段 grant all on *.* to 'egon1'@'localhost'; #授权多有的权限，*.*是user下所有级别的；
grant select on *.* to 'egon1'@'localhost';
revoke select on *.* from 'egon1'@'localhost'; #回收权限 grant select on db1.* to 'egon1'@'localhost';
revoke select on db1.* from 'egon1'@'localhost'; grant select on db1.t1 to 'kris'@'localhost';# -uroot 只放行了对t1的权限
#先查看下 select * from mysql.user\G 看select权限有没有看；再看select * from mysql.db\G 查看下select权限有没开
#select * from mysql.tables_priv\G ,看到有权限了；验证下：exit mysql -ukris1 -p123 -->> show databeses; -->use db1; -->show tables;->select * from t1;
revoke select on db1.t2 from 'egon1'@'localhost'; grant select(id,name),update(age) on db1.t2 to 'egon1'@'localhost'; #精确到字段级别
#select * from mysql.columns_priv;
mysql> create user 'kris1'@'localhost' identified by ''; ##创建本地账号；
Query OK, rows affected (0.39 sec) mysql> select * from mysql.user\G
*************************** . row ***************************
Host: localhost
User: root
Password:
Select_priv: Y
Insert_priv: Y
Update_priv: Y
Delete_priv: Y
.....
max_connections:
max_user_connections:
plugin: mysql_native_password
authentication_string:
password_expired: N
*************************** . row ***************************
Host: 127.0.0.1
User: root
Password:
Select_priv: Y
Insert_priv: Y
Update_priv: Y
Del......
authentication_string:
password_expired: N
*************************** . row ***************************
Host: ::
User: root
Password:
Select_priv: Y
Insert_priv: Y
Update_priv: Y
......
password_expired: N
*************************** . row ***************************
Host: localhost
User:
Password:
Select_priv: N
I.........*************************** . row ***************************
Host: localhost
User: kris1
Password: *23AE809DDACAF96AF0FD78ED04B6A265E05AA257
Select_priv: N #下面的都有N，造出来的权限默认是在user表里边，user没有放行任何权限，但不一定这个用户一定就没有权限；
Insert_priv: N
Update_priv: N
Delete_priv: N
Create_priv: N
Drop_priv: N
Reload_priv: N
Shutdown_priv: N
Process_priv: N
File_priv: N
Grant_priv: N
References_priv: N
Index_priv: N
Alter_priv: N
Show_db_priv: N
Super_priv: N
Create_tmp_table_priv: N
Lock_tables_priv: N
Execute_priv: N
Repl_slave_priv: N
Repl_client_priv: N
Create_view_priv: N
Show_view_priv: N
Create_routine_priv: N
Alter_routine_priv: N
Create_user_priv: N
Event_priv: N
Trigger_priv: N
Create_tablespace_priv: N
ssl_type:
ssl_cipher:
x509_issuer:
x509_subject:
max_questions:
max_updates:
max_connections:
max_user_connections:
plugin: mysql_native_password
authentication_string:
password_expired: N
rows in set (0.05 sec) mysql> select * from mysql.db\G #查看下面的db表
*************************** . row ***************************
Host: % ##有关于库相关的权限，但没有具体到用户，用户都是空的，意味着对任何用户都是有效的，包括刚刚的kris1；%代表任意的，包含localhost
Db: test
User:
Select_priv: Y
Insert_priv: Y
Update_priv: Y
Delete_priv: Y
Create_priv: Y
Drop_priv: Y
Grant_priv: N
References_priv: Y
Index_priv: Y
Alter_priv: Y
Create_tmp_table_priv: Y
Lock_tables_priv: Y
Create_view_priv: Y
Show_view_priv: Y
Create_routine_priv: Y
Alter_routine_priv: N
Execute_priv: N
Event_priv: Y
Trigger_priv: Y
*************************** . row ***************************
Host: %
Db: test\_% #对db下的以 __开头的任意都有权限
User:
Select_priv: Y
Insert_priv: Y
Update_priv: Y
Delete_priv: Y
Create_priv: Y
Drop_priv: Y
Grant_priv: N
References_priv: Y
Index_priv: Y
Alter_priv: Y
Create_tmp_table_priv: Y
Lock_tables_priv: Y
Create_view_priv: Y
Show_view_priv: Y
Create_routine_priv: Y
Alter_routine_priv: N
Execute_priv: N
Event_priv: Y
Trigger_priv: Y
rows in set (0.00 sec) mysql> show databases;
+--------------------+
| Database |
+--------------------+
| information_schema |
| db1 |
| db2 |
| db3 |
| db4 |
| db5 |
| db6 |
| mysql |
| performance_schema |
| test |
+--------------------+
rows in set (0.68 sec) mysql> create database test_1;
Query OK, row affected (0.06 sec) mysql> create database test2;
Query OK, row affected (0.03 sec) mysql> show databases;
+--------------------+
| Database |
+--------------------+
| information_schema |
| db1 |
| db2 |
| db3 |
| db4 |
| db5 |
| db6 |
| mysql |
| performance_schema |
| test |
| test2 |
| test_1 |
+--------------------+
rows in set (0.00 sec) mysql> exit
Bye C:\Users\Administrator>mysql -ukris1 -p123
Warning: Using a password on the command line interface can be insecure.
Welcome to the MySQL monitor. Commands end with ; or \g.
Your MySQL connection id is
Server version: 5.6. MySQL Community Server (GPL) Copyright (c) , , Oracle and/or its affiliates. All rights reserved. Oracle is a registered trademark of Oracle Corporation and/or its
affiliates. Other names may be trademarks of their respective
owners. Type 'help;' or '\h' for help. Type '\c' to clear the current input statement. mysql> show databases;
+--------------------+
| Database |
+--------------------+
| information_schema |
| test |
| test_1 |
+--------------------+
rows in set (0.00 sec) mysql> drop database test_1;
Query OK, rows affected (0.64 sec) mysql> use test;
Database changed
mysql> show tables;
Empty set (0.06 sec)
C:\Users\Administrator>mysql -uroot -p
Enter password:
Welcome to the MySQL monitor. Commands end with ; or \g.
Your MySQL connection id is
Server version: 5.6. MySQL Community Server (GPL) Copyright (c) , , Oracle and/or its affiliates. All rights reserved. Oracle is a registered trademark of Oracle Corporation and/or its
affiliates. Other names may be trademarks of their respective
owners. Type 'help;' or '\h' for help. Type '\c' to clear the current input statement. mysql> grant select on *.* to 'kris1'@'localhost';
Query OK, rows affected (0.01 sec) mysql> select * from mysql.user\G
*************************** . row ***************************
Host: localhost
User: root
Password:
Select_priv: Y
Insert_priv: Y
Update_priv: Y
Delete_priv: Y
Create_priv: Y
Drop_priv: Y
Reload_priv: Y
Shutdown_priv: Y
Process_priv: Y
File_priv: Y
Grant_priv: Y
References_priv: Y
Index_priv: Y
Alter_priv: Y
Show_db_priv: Y
Super_priv: Y
Create_tmp_table_priv: Y
Lock_tables_priv: Y
Execute_priv: Y
Repl_slave_priv: Y
Repl_client_priv: Y
Create_view_priv: Y
Show_view_priv: Y
Create_routine_priv: Y
Alter_routine_priv: Y
Create_user_priv: Y
Event_priv: Y
Trigger_priv: Y
Create_tablespace_priv: Y
ssl_type:
ssl_cipher:
x509_issuer:
x509_subject:
max_questions:
max_updates:
max_connections:
max_user_connections:
plugin: mysql_native_password
authentication_string:
password_expired: N
*************************** . row ***************************
Host: 127.0.0.1
User: root
Password:
Select_priv: Y
Insert_priv: Y
*************************** . row ***************************
Host: ::
User: root
Password:
Select_priv: Y
......
password_expired: N
*************************** . row ***************************
Host: localhost
User:
Password:
Select_priv: N
Insert_priv: N
Update_priv: N
.....
Create_tablespace_priv: N
ssl_type:
.....*************************** . row ***************************
Host: localhost
User: kris1
Password: *23AE809DDACAF96AF0FD78ED04B6A265E05AA257
Select_priv: Y
Insert_priv: N
Update_priv: N
Delete_priv: N
Create_priv: N
Drop_priv: N
Reload_priv: N
Shutdown_priv: N
Process_priv: N
File_priv: N
Grant_priv: N
References_priv: N
Index_priv: N
Alter_priv: N
Show_db_priv: N
Super_priv: N
Create_tmp_table_priv: N
Lock_tables_priv: N
Execute_priv: N
Repl_slave_priv: N
Repl_client_priv: N
Create_view_priv: N
Show_view_priv: N
Create_routine_priv: N
Alter_routine_priv: N
Create_user_priv: N
Event_priv: N
Trigger_priv: N
Create_tablespace_priv: N
ssl_type:
ssl_cipher:
x509_issuer:
x509_subject:
max_questions:
max_updates:
max_connections:
max_user_connections:
plugin: mysql_native_password
authentication_string:
password_expired: N
rows in set (0.05 sec) mysql> exit
Bye C:\Users\Administrator>mysql -ukris1 -p123
Warning: Using a password on the command line interface can be insecure.
Welcome to the MySQL monitor. Commands end with ; or \g.
Your MySQL connection id is
Server version: 5.6. MySQL Community Server (GPL) mysql> show databases;
+--------------------+
| Database |
+--------------------+
| information_schema |
| db1 |
| db2 |
| db3 |
| db4 |
| db5 |
| db6 |
| mysql |
| performance_schema |
| test |
| test2 |
+--------------------+
rows in set (0.05 sec) mysql> use db1;
Database changed
mysql> show tables;
+---------------+
| Tables_in_db1 |
+---------------+
| t1 |
+---------------+
row in set (0.00 sec) mysql> select * from t1;
+------+------+
| id | name |
+------+------+
| | SB |
| | SB |
+------+------+
rows in set (0.24 sec) mysql> insert into t2 values(, 'kris1',);
ERROR (): INSERT command denied to user 'kris1'@'localhost' for table 't2'
mysql>
C:\Users\Administrator>mysql -uroot -p
Enter password:
Welcome to the MySQL monitor. Commands end with ; or \g.
Your MySQL connection id is
Server version: 5.6. MySQL Community Server (GPL) Copyright (c) , , Oracle and/or its affiliates. All rights r Oracle is a registered trademark of Oracle Corporation and/or its
affiliates. Other names may be trademarks of their respective
owners. Type 'help;' or '\h' for help. Type '\c' to clear the current input mysql> revoke select on *.* from 'kris1'@'localhost';
Query OK, rows affected (0.00 sec) mysql> select * from mysql.user\G
*************************** . row ***************************
......
*************************** . row ***************************
Host: localhost
User: kris1
Password: *23AE809DDACAF96AF0FD78ED04B6A265E05AA257
Select_priv: N #又没有权限了
Insert_priv: N
Update_priv: N
Delete_priv: N
Create_priv: N
Drop_priv: N
Reload_priv: N
Shutdown_priv: N
Process_priv: N
File_priv: N
Grant_priv: N
References_priv: N
Index_priv: N
Alter_priv: N
Show_db_priv: N
Super_priv: N
Create_tmp_table_priv: N
Lock_tables_priv: N
Execute_priv: N
Repl_slave_priv: N
Repl_client_priv: N
Create_view_priv: N
Show_view_priv: N
Create_routine_priv: N
Alter_routine_priv: N
Create_user_priv: N
Event_priv: N
Trigger_priv: N
Create_tablespace_priv: N
ssl_type:
ssl_cipher:
x509_issuer:
x509_subject:
max_questions:
max_updates:
max_connections:
max_user_connections:
plugin: mysql_native_password
authentication_string:
password_expired: N
rows in set (0.00 sec)
mysql> grant select on db1.* to 'kris1'@'localhost';
Query OK, rows affected (0.00 sec) mysql> select * from mysql.db\G
*************************** . row ***************************
Host: %
Db: test
User:
Select_priv: Y
Insert_priv: Y
Update_priv: Y
Delete_priv: Y
Create_priv: Y
Drop_priv: Y
Grant_priv: N
References_priv: Y
Index_priv: Y
Alter_priv: Y
Create_tmp_table_priv: Y
Lock_tables_priv: Y
Create_view_priv: Y
Show_view_priv: Y
Create_routine_priv: Y
Alter_routine_priv: N
Execute_priv: N
Event_priv: Y
Trigger_priv: Y
*************************** . row ***************************
Host: %
Db: test\_%
User:
Select_priv: Y
Insert_priv: Y
Update_priv: Y
Delete_priv: Y
Create_priv: Y
Drop_priv: Y
Grant_priv: N
References_priv: Y
Index_priv: Y
Alter_priv: Y
Create_tmp_table_priv: Y
Lock_tables_priv: Y
Create_view_priv: Y
Show_view_priv: Y
Create_routine_priv: Y
Alter_routine_priv: N
Execute_priv: N
Event_priv: Y
Trigger_priv: Y
*************************** . row ***************************
Host: localhost
Db: db1
User: kris1
Select_priv: Y
Insert_priv: N
Update_priv: N
Delete_priv: N
Create_priv: N
Drop_priv: N
Grant_priv: N
References_priv: N
Index_priv: N
Alter_priv: N
Create_tmp_table_priv: N
Lock_tables_priv: N
Create_view_priv: N
Show_view_priv: N
Create_routine_priv: N
Alter_routine_priv: N
Execute_priv: N
Event_priv: N
Trigger_priv: N
rows in set (0.00 sec) mysql> exit
Bye C:\Users\Administrator>mysql -ukris1 -p123
Warning: Using a password on the command line interface can be insecure.
Welcome to the MySQL monitor. Commands end with ; or \g.
Your MySQL connection id is
Server version: 5.6. MySQL Community Server (GPL) Copyright (c) , , Oracle and/or its affiliates. All rights reserved. Oracle is a registered trademark of Oracle Corporation and/or its
affiliates. Other names may be trademarks of their respective
owners. Type 'help;' or '\h' for help. Type '\c' to clear the current input statement. mysql> show databases;
+--------------------+
| Database |
+--------------------+
| information_schema |
| db1 |
| test |
+--------------------+
rows in set (0.00 sec) mysql> use db1;
Database changed
mysql> show tables;
+---------------+
| Tables_in_db1 |
+---------------+
| t1 |
+---------------+
row in set (0.00 sec) mysql> select * from t1;
+------+------+
| id | name |
+------+------+
| | SB |
| | SB |
+------+------+
rows in set (0.00 sec) mysql> insert into t1 values(,'SB');
ERROR (): INSERT command denied to user 'kris1'@'localhost' for table 't
mysql> exit
Bye C:\Users\Administrator>mysql -uroot -p
Enter password:
Welcome to the MySQL monitor. Commands end with ; or \g.
Your MySQL connection id is
Server version: 5.6. MySQL Community Server (GPL) Copyright (c) , , Oracle and/or its affiliates. All rights reserved. Oracle is a registered trademark of Oracle Corporation and/or its
affiliates. Other names may be trademarks of their respective
owners. Type 'help;' or '\h' for help. Type '\c' to clear the current input statement. mysql> revoke select on db1.* from 'kris1'@'localhost';
Query OK, rows affected (0.00 sec)
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