How to query data in mysql (process)

MySQL is an open source relational database management system. Its process consists of the following five parts:

1. Connecting to the MySQL server

Connecting to the MySQL server is the first step of using MySQL. step. Through the TCP/IP protocol, the client program can connect to the server. When connecting to the MySQL server, you need to provide the host name, user name and password. If the username and password are verified successfully, you can start using the MySQL server.

2. Send SQL queries

Once a connection is established with the MySQL server, the client program can send SQL queries to the server. SQL queries can be used to modify the database, such as adding, modifying, and deleting data, and can also be used to query data.

3. Query Parsing and Optimization

Once the server receives a SQL query, it parses and optimizes the query. Parsing a SQL query means converting the SQL query into commands that the server can understand. Optimizing a SQL query means trying to understand the query requirements and determining how to retrieve the data most efficiently.

4. Processing queries

Processing queries means that the MySQL server executes SQL queries and retrieves the corresponding data. Executing queries is divided into different tasks such as reading data, filtering data, sorting data, grouping data, combining data from multiple tables, etc. The MySQL server decides how to execute the query based on the complexity of the query and server performance.

5. Return results

Once the MySQL server completes the query, it returns the results to the client. The result can be the success or failure information of modifying the database, or the result of the query. Results can be returned to the client via the command line, web page, or API.

In general, the MySQL process is an interactive process. The client program sends an SQL query to the server, the server parses and optimizes the query, retrieves and processes the data, and finally returns the results to the client program. This interactive process is the core of MySQL operation.

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