Python MySQL SELECT Query: Fetching Data from Your Database

Working with databases is a crucial part of web development. Whether you’re building a blog, e-commerce site, or a learning platform, fetching data efficiently is essential. In this post, we'll explore how to use Python to perform a SELECT query on a MySQL database using the mysql-connector-python library.

Prerequisites

Before we get started, make sure:

• You have MySQL installed and running.
• Python is installed on your system.
• You’ve installed the MySQL connector:

pip install mysql-connector-python

Step 1: Connect to MySQL Database

First, import the required library and establish a connection:

import mysql.connector

# Connect to your MySQL database
conn = mysql.connector.connect(
    host="localhost",      # or your DB host
    user="yourusername",   # your DB username
    password="yourpassword",
    database="yourdatabase"
)

cursor = conn.cursor()

Step 2: Write and Execute the SELECT Query

Let’s assume you have a table called blogs. To fetch all blog posts, you can run:

query = "SELECT * FROM blogs"
cursor.execute(query)

You can also fetch only specific columns:

query = "SELECT title, author FROM blogs"
cursor.execute(query)

Step 3: Fetch the Results

Use one of the following methods:

• fetchall() – to get all rows
• fetchone() – to get a single row

Example:

results = cursor.fetchall()
for row in results:
    print("Title:", row[0], "| Author:", row[1])

Sample Output:

Title: Learn Python | Author: Admin
Title: MySQL Basics | Author: John

Step 4: Close the Connection

Don’t forget to close the cursor and connection:

cursor.close()
conn.close()

Final Notes

• Always sanitize input to prevent SQL injection.
• For dynamic queries, use parameterized queries with placeholders (%s).

Example:

query = "SELECT * FROM blogs WHERE author = %s"
cursor.execute(query, ("John",))