zbb20180619 MySQL Common commands

Show DATABASES can display all the databases,

Show TABLES will display all the data sheets,

Show all users in MySQL

1. Log in to the database

First of all, you need to log in to the database using the following command, note that must be root user Oh ~

# # Mysql-u Root-p

2. Querying user Tables

In MySQL in fact there is a built-in database named MySQL , the database is stored in some MySQL data, such as users, permissions information, stored procedures, and so on, we can use the following simple query statement to display all users.

SELECT User, Host, Password from Mysql.user;

SELECT DISTINCT User from Mysql.user;

MySQL Add user, delete user and authorization

MySQL add user, new database, user authorization, delete user, change password (note that each line followed by A; indicates that a command statement ends):

1. Create a new user

1.1 Log in to MySQL:

@>mysql-u root-p

@> Password

1.2 Create User:

mysql> INSERT INTO Mysql.user (Host,user,password) VALUES ("localhost", "Test", Password ("1234"));

This creates a user named: Test with a password of: 1234.

　　Note: "localhost" here means that the user can only log on locally and cannot telnet to another machine. If you want to telnet, change "localhost" to "%", which means you can log on on any computer. You can also specify that a machine can log on remotely.

1.3 Then log in:

mysql>exit;

@>mysql-u test-p

@> Enter password

Mysql> Login Successful

2. Authorizing the user

Authorization format: Grant permissions on database. * To User name @ login host identified by "password";

2.1 Log in to MySQL (rooted), log in as root here:

@>mysql-u root-p

@> Password

2.2 First create a database for the user (TestDB):

Mysql>create database TestDB;

2.3 Authorization test the user has all permissions for the TestDB database (all permissions for a database):

Mysql>grant all privileges in testdb.* to [e-mail protected] identified by ' 1234 ';

Mysql>flush privileges;//Refresh System Permissions Table

Format: Grant permissions on database. * To User name @ login host identified by "password";

2.4 If you want to specify a partial permission to a user, you can write:

Mysql>grant select,update on testdb.* to [e-mail protected] identified by ' 1234 ';

Mysql>flush privileges; Refresh System Permissions Table

2.5 Authorization test The user has some permissions for all databases:

Mysql>grant Select,delete,update,create,drop on * * To test@ "%" identified by "1234";

The test user has Select,delete,update,create,drop permissions on all databases.

@ "%" indicates authorization for all non-local hosts, excluding localhost. (The localhost address is set to 127.0.0.1, if set to the real local address, do not know whether it can, no authentication.) )

Authorization to localhost: plus a grant all privileges on testdb.* to [email protected] identified by ' 1234 ';

3. Delete a user

@>mysql-u root-p

@> Password

Mysql>delete from user Where user= ' test ' and host= ' localhost ';

Mysql>flush privileges;

Mysql>drop database TestDB; Delete a user's database

Delete account and permissions: >drop user username @ '% ';

>drop user username @ localhost;

4. Modify the specified user password

@>mysql-u root-p

@> Password

Mysql>update Mysql.user Set Password=password (' New password ') where user= "test" and host= "localhost";

Mysql>flush privileges;

5. List all databases

Mysql>show database;

6. Switching the database

Mysql>use ' database name ';

7. List all Tables

Mysql>show tables;

8. Display the data table structure

Mysql>describe table name;

9. Deleting databases and data tables

Mysql>drop database name;

Mysql>drop table Data Sheet name;

zbb20180619 MySQL Common commands