MariaDB

MariaDB基础应用

1、创建testdb数据库，并设置为默认库

MariaDB [(none)]> CREATE DATABASE testdb;
Query OK, 1 row affected (0.00 sec)MariaDB [(none)]> use testdb
Database changed
MariaDB [testdb]>

2、创建学生表

2.1 创建学生表；

id字段为int整型，不使用符号，不能为空，设为主键；
name字段为可变长字段（20字符），不能为空；
age字段为最小整型（0-255），不使用符号；MariaDB [testdb]> CREATE TABLE students (id int UNSIGNED NOT NULL PRIMARY KEY,name VARCHAR(20) NOT NULL,age tinyint UNSIGNED);

2.2 查看学生表结构

MariaDB [testdb]> DESC students;
+-------+---------------------+------+-----+---------+-------+
| Field | Type                | Null | Key | Default | Extra |
+-------+---------------------+------+-----+---------+-------+
| id    | int(10) unsigned    | NO   | PRI | NULL    |       |
| name  | varchar(20)         | NO   |     | NULL    |       |
| age   | tinyint(3) unsigned | YES  |     | NULL    |       |
+-------+---------------------+------+-----+---------+-------+
3 rows in set (0.01 sec)MariaDB [testdb]>

2.3 创建tbl2表，定义两个主键方法

MariaDB [testdb]> CREATE TABLE tbl2 (id int UNSIGNED NOT NULL,name VARCHAR(20) NOT NULL,age tinyint UNSIGNED, PRIMARY KEY(id,name));
Query OK, 0 rows affected (0.02 sec)MariaDB [testdb]> DESC tbl2;
+-------+---------------------+------+-----+---------+-------+
| Field | Type                | Null | Key | Default | Extra |
+-------+---------------------+------+-----+---------+-------+
| id    | int(10) unsigned    | NO   | PRI | NULL    |       |
| name  | varchar(20)         | NO   | PRI | NULL    |       |
| age   | tinyint(3) unsigned | YES  |     | NULL    |       |
+-------+---------------------+------+-----+---------+-------+
3 rows in set (0.00 sec)MariaDB [testdb]>

3、查看student表时由哪些命令创建的

MariaDB [testdb]> SHOW CREATE TABLE students;
+----------+--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+
| Table    | Create Table                                                                                                                                                                                     |
+----------+--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+
| students | CREATE TABLE `students` (`id` int(10) unsigned NOT NULL,`name` varchar(20) NOT NULL,`age` tinyint(3) unsigned DEFAULT NULL,PRIMARY KEY (`id`)
) ENGINE=InnoDB DEFAULT CHARSET=latin1 |
+----------+--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+
1 row in set (0.00 sec)

查看表状态

MariaDB [testdb]> SHOW TABLE STATUS LIKE 'students'\G
*************************** 1. row ***************************Name: studentsEngine: InnoDBVersion: 10Row_format: CompactRows: 0Avg_row_length: 0Data_length: 16384
Max_data_length: 0Index_length: 0Data_free: 10485760Auto_increment: NULLCreate_time: 2016-08-30 15:41:41Update_time: NULLCheck_time: NULLCollation: latin1_swedish_ciChecksum: NULLCreate_options: Comment:
1 row in set (0.00 sec)

获取修改表的帮助

MariaDB [testdb]> HELP ALTER TABLE;

修改表

1、在students表里添加gender字段，并放在最后面

MariaDB [testdb]> ALTER TABLE students ADD gender ENUM('m','f');
Query OK, 0 rows affected (0.09 sec)
Records: 0  Duplicates: 0  Warnings: 0MariaDB [testdb]> DESC students;
+--------+---------------------+------+-----+---------+-------+
| Field  | Type                | Null | Key | Default | Extra |
+--------+---------------------+------+-----+---------+-------+
| id     | int(10) unsigned    | NO   | PRI | NULL    |       |
| name   | varchar(20)         | NO   |     | NULL    |       |
| age    | tinyint(3) unsigned | YES  |     | NULL    |       |
| gender | enum('m','f')       | YES  |     | NULL    |       |
+--------+---------------------+------+-----+---------+-------+
4 rows in set (0.00 sec)MariaDB [testdb]>

2、更改id字段名为sdid，需要把字段类型加上去，类型修饰符必须紧跟在类型后面；主键默认永久存在不需要再定义

MariaDB [testdb]> ALTER TABLE students CHANGE id sid int UNSIGNED NOT NULL;
Query OK, 0 rows affected (0.03 sec)
Records: 0  Duplicates: 0  Warnings: 0MariaDB [testdb]> DESC students;
+--------+---------------------+------+-----+---------+-------+
| Field  | Type                | Null | Key | Default | Extra |
+--------+---------------------+------+-----+---------+-------+
| sid    | int(10) unsigned    | NO   | PRI | NULL    |       |
| name   | varchar(20)         | NO   |     | NULL    |       |
| age    | tinyint(3) unsigned | YES  |     | NULL    |       |
| gender | enum('m','f')       | YES  |     | NULL    |       |
+--------+---------------------+------+-----+---------+-------+
4 rows in set (0.00 sec)

5、删除字段

MariaDB [testdb]> DESC stutdents-> ;
ERROR 1146 (42S02): Table 'testdb.stutdents' doesn't exist
MariaDB [testdb]> DESC students;
+--------+---------------------+------+-----+---------+-------+
| Field  | Type                | Null | Key | Default | Extra |
+--------+---------------------+------+-----+---------+-------+
| sid    | int(10) unsigned    | NO   | PRI | NULL    |       |
| name   | varchar(20)         | NO   |     | NULL    |       |
| age    | tinyint(3) unsigned | YES  |     | NULL    |       |
| gender | enum('m','f')       | YES  |     | NULL    |       |
| qq     | int(11)             | YES  |     | NULL    |       |
+--------+---------------------+------+-----+---------+-------+
5 rows in set (0.00 sec)MariaDB [testdb]> ALTER TABLE students DROP qq;
Query OK, 0 rows affected (0.03 sec)
Records: 0  Duplicates: 0  Warnings: 0MariaDB [testdb]> DESC students;
+--------+---------------------+------+-----+---------+-------+
| Field  | Type                | Null | Key | Default | Extra |
+--------+---------------------+------+-----+---------+-------+
| sid    | int(10) unsigned    | NO   | PRI | NULL    |       |
| name   | varchar(20)         | NO   |     | NULL    |       |
| age    | tinyint(3) unsigned | YES  |     | NULL    |       |
| gender | enum('m','f')       | YES  |     | NULL    |       |
+--------+---------------------+------+-----+---------+-------+
4 rows in set (0.00 sec)MariaDB [testdb]>

6、在name字段添加唯一键约束

MariaDB [testdb]> ALTER TABLE students ADD UNIQUE KEY(name);
Query OK, 0 rows affected (0.04 sec)
Records: 0  Duplicates: 0  Warnings: 0MariaDB [testdb]> DESC students;
+--------+---------------------+------+-----+---------+-------+
| Field  | Type                | Null | Key | Default | Extra |
+--------+---------------------+------+-----+---------+-------+
| sid    | int(10) unsigned    | NO   | PRI | NULL    |       |
| name   | varchar(20)         | NO   | UNI | NULL    |       |
| age    | tinyint(3) unsigned | YES  |     | NULL    |       |
| gender | enum('m','f')       | YES  |     | NULL    |       |
+--------+---------------------+------+-----+---------+-------+
4 rows in set (0.00 sec)MariaDB [testdb]>

7、年龄字段添加索引

MariaDB [testdb]> ALTER TABLE students ADD INDEX(age);
Query OK, 0 rows affected (0.09 sec)
Records: 0  Duplicates: 0  Warnings: 0MariaDB [testdb]> DESC students-> ;
+--------+---------------------+------+-----+---------+-------+
| Field  | Type                | Null | Key | Default | Extra |
+--------+---------------------+------+-----+---------+-------+
| sid    | int(10) unsigned    | NO   | PRI | NULL    |       |
| name   | varchar(20)         | NO   | UNI | NULL    |       |
| age    | tinyint(3) unsigned | YES  | MUL | NULL    |       |
| gender | enum('m','f')       | YES  |     | NULL    |       |
+--------+---------------------+------+-----+---------+-------+
4 rows in set (0.00 sec)查看一个表的索引：
MariaDB [testdb]> SHOW INDEXES FROM students;
+----------+------------+----------+--------------+-------------+-----------+-------------+----------+--------+------+------------+---------+---------------+
| Table    | Non_unique | Key_name | Seq_in_index | Column_name | Collation | Cardinality | Sub_part | Packed | Null | Index_type | Comment | Index_comment |
+----------+------------+----------+--------------+-------------+-----------+-------------+----------+--------+------+------------+---------+---------------+
| students |          0 | PRIMARY  |            1 | sid         | A         |           0 |     NULL | NULL   |      | BTREE      |         |               |
| students |          0 | name     |            1 | name        | A         |           0 |     NULL | NULL   |      | BTREE      |         |               |
| students |          1 | age      |            1 | age         | A         |           0 |     NULL | NULL   | YES  | BTREE      |         |               |
+----------+------------+----------+--------------+-------------+-----------+-------------+----------+--------+------+------------+---------+---------------+
3 rows in set (0.00 sec)

8、删除索引

MariaDB [testdb]> ALTER TABLE students DROP age;
Query OK, 0 rows affected (0.10 sec)
Records: 0  Duplicates: 0  Warnings: 0MariaDB [testdb]> SHOW INDEXES FROM students;
+----------+------------+----------+--------------+-------------+-----------+-------------+----------+--------+------+------------+---------+---------------+
| Table    | Non_unique | Key_name | Seq_in_index | Column_name | Collation | Cardinality | Sub_part | Packed | Null | Index_type | Comment | Index_comment |
+----------+------------+----------+--------------+-------------+-----------+-------------+----------+--------+------+------------+---------+---------------+
| students |          0 | PRIMARY  |            1 | sid         | A         |           0 |     NULL | NULL   |      | BTREE      |         |               |
| students |          0 | name     |            1 | name        | A         |           0 |     NULL | NULL   |      | BTREE      |         |               |
+----------+------------+----------+--------------+-------------+-----------+-------------+----------+--------+------+------------+---------+---------------+
2 rows in set (0.00 sec)

9、删除索引

MariaDB [testdb]> DROP INDEX name ON students;
Query OK, 0 rows affected (0.04 sec)
Records: 0  Duplicates: 0  Warnings: 0MariaDB [testdb]> SHOW INDEX FROM students;
+----------+------------+----------+--------------+-------------+-----------+-------------+----------+--------+------+------------+---------+---------------+
| Table    | Non_unique | Key_name | Seq_in_index | Column_name | Collation | Cardinality | Sub_part | Packed | Null | Index_type | Comment | Index_comment |
+----------+------------+----------+--------------+-------------+-----------+-------------+----------+--------+------+------------+---------+---------------+
| students |          0 | PRIMARY  |            1 | sid         | A         |           0 |     NULL | NULL   |      | BTREE      |         |               |
+----------+------------+----------+--------------+-------------+-----------+-------------+----------+--------+------+------------+---------+---------------+
1 row in set (0.00 sec)MariaDB [testdb]>

DML：INSET,DELETE,SELECT,UPDATE

INSERT

插入两行数据

MariaDB [testdb]> INSERT INTO students VALUES (1,'Yang Guo','m'),(2,'Guo Xiang','f');
Query OK, 2 rows affected (0.07 sec)
Records: 2  Duplicates: 0  Warnings: 0MariaDB [testdb]> SELECT * FROM students;
+-----+-----------+--------+
| sid | name      | gender |
+-----+-----------+--------+
|   1 | Yang Guo  | m      |
|   2 | Guo Xiang | f      |
+-----+-----------+--------+
2 rows in set (0.00 sec)MariaDB [testdb]>

gender项可以为空，再插入二行数据

MariaDB [testdb]> INSERT INTO students (sid,name) VALUES (3,'Zhang Wuji'),(4,'Zhao Min');
Query OK, 2 rows affected (0.01 sec)
Records: 2  Duplicates: 0  Warnings: 0MariaDB [testdb]> SELECT * FROM students;
+-----+------------+--------+
| sid | name       | gender |
+-----+------------+--------+
|   1 | Yang Guo   | m      |
|   2 | Guo Xiang  | f      |
|   3 | Zhang Wuji | NULL   |
|   4 | Zhao Min   | NULL   |
+-----+------------+--------+
4 rows in set (0.00 sec)MariaDB [testdb]>

SELECT

查询整张表的内容

MariaDB [testdb]> SELECT * FROM students;
+-----+------------+--------+
| sid | name       | gender |
+-----+------------+--------+
|   1 | Yang Guo   | m      |
|   2 | Guo Xiang  | f      |
|   3 | Zhang Wuji | NULL   |
|   4 | Zhao Min   | NULL   |
+-----+------------+--------+
4 rows in set (0.00 sec)

查询所有sid小于3的行

MariaDB [testdb]> SELECT * FROM students WHERE sid<3;
+-----+-----------+--------+
| sid | name      | gender |
+-----+-----------+--------+
|   1 | Yang Guo  | m      |
|   2 | Guo Xiang | f      |
+-----+-----------+--------+
2 rows in set (0.06 sec)MariaDB [testdb]>

查看gender=m的行

MariaDB [testdb]> SELECT * FROM students WHERE gender='m';
+-----+----------+--------+
| sid | name     | gender |
+-----+----------+--------+
|   1 | Yang Guo | m      |
+-----+----------+--------+
1 row in set (0.05 sec)MariaDB [testdb]>

显示gender值为空的行

MariaDB [testdb]> SELECT * FROM students WHERE gender IS NULL;
+-----+------------+--------+
| sid | name       | gender |
+-----+------------+--------+
|   3 | Zhang Wuji | NULL   |
|   4 | Zhao Min   | NULL   |
+-----+------------+--------+
2 rows in set (0.03 sec)MariaDB [testdb]>

显示gender值不为空的行

MariaDB [testdb]> SELECT * FROM students WHERE gender IS NOT NULL;
+-----+-----------+--------+
| sid | name      | gender |
+-----+-----------+--------+
|   1 | Yang Guo  | m      |
|   2 | Guo Xiang | f      |
+-----+-----------+--------+
2 rows in set (0.00 sec)MariaDB [testdb]>

查找表的所有内容，并根据名字排序

MariaDB [testdb]> SELECT * FROM students ORDER BY name;
+-----+------------+--------+
| sid | name       | gender |
+-----+------------+--------+
|   2 | Guo Xiang  | f      |
|   1 | Yang Guo   | m      |
|   3 | Zhang Wuji | NULL   |
|   4 | Zhao Min   | NULL   |
+-----+------------+--------+
4 rows in set (0.04 sec)MariaDB [testdb]> 降序排序
MariaDB [testdb]> SELECT * FROM students ORDER BY name DESC;
+-----+------------+--------+
| sid | name       | gender |
+-----+------------+--------+
|   4 | Zhao Min   | NULL   |
|   3 | Zhang Wuji | NULL   |
|   1 | Yang Guo   | m      |
|   2 | Guo Xiang  | f      |
+-----+------------+--------+
4 rows in set (0.00 sec)MariaDB [testdb]>

名字降序排序，并只显示前两个

MariaDB [testdb]> SELECT * FROM students ORDER BY name DESC LIMIT 2;
+-----+------------+--------+
| sid | name       | gender |
+-----+------------+--------+
|   4 | Zhao Min   | NULL   |
|   3 | Zhang Wuji | NULL   |
+-----+------------+--------+
2 rows in set (0.00 sec)跳过第一个，显示前两个
MariaDB [testdb]> SELECT * FROM students ORDER BY name DESC LIMIT 1,2;
+-----+------------+--------+
| sid | name       | gender |
+-----+------------+--------+
|   3 | Zhang Wuji | NULL   |
|   1 | Yang Guo   | m      |
+-----+------------+--------+
2 rows in set (0.00 sec)

显示SID大于等于2小于等于4的行

MariaDB [testdb]> SELECT * FROM students WHERE sid>=2 and sid <=4;
+-----+------------+--------+
| sid | name       | gender |
+-----+------------+--------+
|   2 | Guo Xiang  | f      |
|   3 | Zhang Wuji | NULL   |
|   4 | Zhao Min   | NULL   |
+-----+------------+--------+
3 rows in set (0.00 sec)第二种写法,BETWEEN 2个值之间：
MariaDB [testdb]> SELECT * FROM students WHERE sid BETWEEN 2 AND 4;
+-----+------------+--------+
| sid | name       | gender |
+-----+------------+--------+
|   2 | Guo Xiang  | f      |
|   3 | Zhang Wuji | NULL   |
|   4 | Zhao Min   | NULL   |
+-----+------------+--------+
3 rows in set (0.01 sec)MariaDB [testdb]>

显示name字段Z开头的行

MariaDB [testdb]> SELECT * FROM students WHERE name LIKE 'Z%';
+-----+------------+--------+
| sid | name       | gender |
+-----+------------+--------+
|   3 | Zhang Wuji | NULL   |
|   4 | Zhao Min   | NULL   |
+-----+------------+--------+
2 rows in set (0.00 sec)MariaDB [testdb]>

使用正则表达式查询行中带u的行；

MariaDB [testdb]> SELECT * FROM students WHERE name RLIKE '.*u.*';
+-----+------------+--------+
| sid | name       | gender |
+-----+------------+--------+
|   1 | Yang Guo   | m      |
|   2 | Guo Xiang  | f      |
|   3 | Zhang Wuji | NULL   |
+-----+------------+--------+
3 rows in set (0.04 sec)MariaDB [testdb]>

用正则表达式查找前面一个大写字母（A-G）后面带u的行

MariaDB [testdb]> SELECT * FROM students WHERE name RLIKE '.*[A-G]u.*';+-----+-----------+--------+
| sid | name      | gender |
+-----+-----------+--------+
|   1 | Yang Guo  | m      |
|   2 | Guo Xiang | f      |
+-----+-----------+--------+
2 rows in set (0.01 sec)MariaDB [testdb]>

查询整张表的内容，并将sid字段别名为stuid，将name字段别名为 stuname，

MariaDB [testdb]> SELECT sid as stuid,name as stuname FROM students;
+-------+------------+
| stuid | stuname    |
+-------+------------+
|     1 | Yang Guo   |
|     2 | Guo Xiang  |
|     3 | Zhang Wuji |
|     4 | Zhao Min   |
+-------+------------+
4 rows in set (0.03 sec)

DELTE

删除sid=3的行

MariaDB [testdb]> DELETE FROM students WEHRE sid=3;
ERROR 1064 (42000): You have an error in your SQL syntax; check the manual that corresponds to your MariaDB server version for the right syntax to use near 'WEHRE sid=3' at line 1
MariaDB [testdb]> DELETE FROM students WHERE sid=3;
Query OK, 1 row affected (0.07 sec)MariaDB [testdb]>
MariaDB [testdb]> SELECT * FROM students;
+-----+-----------+--------+
| sid | name      | gender |
+-----+-----------+--------+
|   1 | Yang Guo  | m      |
|   2 | Guo Xiang | f      |
|   4 | Zhao Min  | NULL   |
+-----+-----------+--------+
3 rows in set (0.00 sec)

UPDATE

修改sid为4的gender值为f

MariaDB [testdb]> UPDATE students SET gender='f' WHERE sid=4;
Query OK, 1 row affected (0.04 sec)
Rows matched: 1  Changed: 1  Warnings: 0MariaDB [testdb]> SELECT * FROM students;
+-----+-----------+--------+
| sid | name      | gender |
+-----+-----------+--------+
|   1 | Yang Guo  | m      |
|   2 | Guo Xiang | f      |
|   4 | Zhao Min  | f      |
+-----+-----------+--------+
3 rows in set (0.00 sec)MariaDB [testdb]>

创建用户账号

1、创建用户

MariaDB [(none)]> CREATE USER 'wpuser'@'%' IDENTIFIED BY 'wpp@ss';
Query OK, 0 rows affected (0.01 sec)MariaDB [mysql]> SELECT User,Host,Password FROM user;
+--------+-----------+-------------------------------------------+
| User   | Host      | Password                                  |
+--------+-----------+-------------------------------------------+
| root   | localhost | *E74858DB86EBA20BC33D0AECAE8A8108C56B17FA |
| root   | qq        | *E74858DB86EBA20BC33D0AECAE8A8108C56B17FA |
| root   | 127.0.0.1 | *E74858DB86EBA20BC33D0AECAE8A8108C56B17FA |
| root   | ::1       | *E74858DB86EBA20BC33D0AECAE8A8108C56B17FA |
|        | localhost |                                           |
|        | qq        |                                           |
| wpuser | 127.0.0.1 | *E4C14E76CFB222E64362BA03BC3F5A0206E7F0E8 |
| wpuser | %         | *D763A435C015D6AA05A435779E5D9CB9B6266278 |
+--------+-----------+-------------------------------------------+
8 rows in set (0.00 sec)登陆测试[root@qq ~]# mysql -u wpuser -h 10.201.106.130 -p
Enter password: mysql> SHOW DATABASES-> ;
+--------------------+
| Database           |
+--------------------+
| information_schema |
| test               |
+--------------------+
2 rows in set (0.00 sec)

用户权限

查看用户权限

MariaDB [(none)]> SHOW GRANTS FOR 'wpuser'@'%';
+-------------------------------------------------------------------------------------------------------+
| Grants for wpuser@%                                                                                   |
+-------------------------------------------------------------------------------------------------------+
| GRANT USAGE ON *.* TO 'wpuser'@'%' IDENTIFIED BY PASSWORD '*D763A435C015D6AA05A435779E5D9CB9B6266278' |
+-------------------------------------------------------------------------------------------------------+
1 row in set (0.00 sec)MariaDB [(none)]>

查看root管理员权限

显示当前用户权限

    MariaDB [(none)]> SHOW GRANTS FOR CURRENT_USER;+----------------------------------------------------------------------------------------------------------------------------------------+| Grants for root@localhost                                                                                                              |+----------------------------------------------------------------------------------------------------------------------------------------+| GRANT ALL PRIVILEGES ON *.* TO 'root'@'localhost' IDENTIFIED BY PASSWORD '*E74858DB86EBA20BC33D0AECAE8A8108C56B17FA' WITH GRANT OPTION || GRANT PROXY ON ''@'' TO 'root'@'localhost' WITH GRANT OPTION                                                                           |+----------------------------------------------------------------------------------------------------------------------------------------+2 rows in set (0.00 sec)MariaDB [(none)]> MariaDB [(none)]> SHOW GRANTS FOR CURRENT_USER();+----------------------------------------------------------------------------------------------------------------------------------------+| Grants for root@localhost                                                                                                              |+----------------------------------------------------------------------------------------------------------------------------------------+| GRANT ALL PRIVILEGES ON *.* TO 'root'@'localhost' IDENTIFIED BY PASSWORD '*E74858DB86EBA20BC33D0AECAE8A8108C56B17FA' WITH GRANT OPTION |
| GRANT PROXY ON ''@'' TO 'root'@'localhost' WITH GRANT OPTION                                                                           |
+----------------------------------------------------------------------------------------------------------------------------------------+
2 rows in set (0.00 sec)MariaDB [(none)]>

用户授权

创建用户并授权，然后远程登录测试

1、创建用户并授权
MariaDB [(none)]> GRANT SELECT,DELETE ON testdb.*TO 'testuser'@'%' IDENTIFIED BY 'testpass';
Query OK, 0 rows affected (0.00 sec)MariaDB [(none)]> 2、登录测试
mysql>
mysql> SHOW DATABASES;
+--------------------+
| Database           |
+--------------------+
| information_schema |
| test               |
| testdb             |
+--------------------+
3 rows in set (0.01 sec)mysql> use testdb
Database changed
mysql>
mysql> SHOW GRANTS FOR CURRENT_USER;
+---------------------------------------------------------------------------------------------------------+
| Grants for testuser@%                                                                                   |
+---------------------------------------------------------------------------------------------------------+
| GRANT USAGE ON *.* TO 'testuser'@'%' IDENTIFIED BY PASSWORD '*00E247AC5F9AF26AE0194B41E1E769DEE1429A29' |
| GRANT SELECT, DELETE ON `testdb`.* TO 'testuser'@'%'                                                    |
+---------------------------------------------------------------------------------------------------------+
2 rows in set (0.01 sec)mysql> 3、权限测试
mysql> CREATE TABLE tbl2 (id int);
ERROR 1142 (42000): CREATE command denied to user 'testuser'@'10.201.106.129' for table 'tbl2'
mysql>
mysql> SELECT * FROM students;
+-----+-----------+--------+
| sid | name      | gender |
+-----+-----------+--------+
|   1 | Yang Guo  | m      |
|   2 | Guo Xiang | f      |
|   4 | Zhao Min  | f      |
+-----+-----------+--------+
3 rows in set (0.01 sec)mysql> mysql> DELETE FROM students where sid=4;
Query OK, 1 row affected (0.05 sec)mysql> SELECT * FROM students;
+-----+-----------+--------+
| sid | name      | gender |
+-----+-----------+--------+
|   1 | Yang Guo  | m      |
|   2 | Guo Xiang | f      |
+-----+-----------+--------+
2 rows in set (0.00 sec)mysql>

权限回收

MariaDB [(none)]> REVOKE DELETE ON testdb.* FROM 'testuser'@'%';
Query OK, 0 rows affected (0.00 sec)MariaDB [(none)]>
MariaDB [(none)]> SHOW GRANTS FOR 'testuser'@'%';
+---------------------------------------------------------------------------------------------------------+
| Grants for testuser@%                                                                                   |
+---------------------------------------------------------------------------------------------------------+
| GRANT USAGE ON *.* TO 'testuser'@'%' IDENTIFIED BY PASSWORD '*00E247AC5F9AF26AE0194B41E1E769DEE1429A29' |
| GRANT SELECT ON `testdb`.* TO 'testuser'@'%'                                                            |
+---------------------------------------------------------------------------------------------------------+
2 rows in set (0.00 sec)

转载于:https://blog.51cto.com/zhongle21/2091445

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