Basic operation of MySQL based on Linux operating system (III)

Basic operation of MySQL based on Linux operating system (III)

• Knowledge Point one: View all users in the MySQL database

Command: SELECT DISTINCT concat (' User: ', user, ' @ ', host, '; ') as query from Mysql.user;

Note: (1) keyword DISTINCT is used to return only different values.

Syntax: SELECT DISTINCT column name from table name

(2) TheSQL concat function is used to concatenate two strings together to form a single string.

Compare the usage of both:

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• Knowledge Point two: View the permissions of a specific user in a database

(1) Command: Show grants for ' cacti ' @ ' 127.0.0.1 ';

As follows:

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(2) Command: SELECT * from Mysql.user where user= ' cacti ' \g;

As follows:

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• Knowledge Point three: Viewing the user table structure requires specific items that can be queried in conjunction with the table structure

Order: desc Mysql.user;

As follows:

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• Knowledge Point four: delete users

Command: Delete from mysql.user where user= ' cacti ' and host= ' 127.0.0.1 ' \g;

As follows:

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Note:mysql>flush privileges; (Refresh database)

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

This article is from the "Hand of the Paladin Control" blog, please make sure to keep this source http://wutengfei.blog.51cto.com/10942117/1913714

Basic operation of MySQL based on Linux operating system (III)