The role of use in mysql

MySQL's USE command is used to select the database to be used in a session and apply subsequent queries and operations to the specified database.

The role of the USE command in MySQL

Introduction
The USE command in MySQL to select the database to use. It tells MySQL to apply subsequent queries and operations to the specified database.

Syntax

<code class="sql">USE database_name;</code>

Function
The USE command performs the following operations:

• Select the specified database.
• Apply subsequent queries and operations to the selected database.
• Affects the current database in all subsequent sessions.

Example

<code class="sql">USE my_database;

SELECT * FROM users; -- 查询 my_database 中的 users 表</code>

Advantages
The advantages of using the USE command include:

• Explicit database selection: It explicitly specifies the database to use, avoiding ambiguity and unexpected errors.
• Session level settings: The USE command sets the current database at the session level, affecting all subsequent operations.
• Easy switching: It makes it easy to switch between multiple databases.

Notes
The following are some notes when using the USE command:

• If the specified database does not exist, MySQL will return mistake.
• The USE command does not create a database. To create a database, use the CREATE DATABASE command.
• The USE command does not affect the current database of other sessions. Each session has its own current database settings.

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