How to Use Python MySQL Update Query – Step-by-Step Guide

When working with databases in your website or app, it's common to update existing records — like changing a user’s email address or updating order status. Python, when used with MySQL, makes this process simple and efficient using the UPDATE query.

In this article, you’ll learn how to:

• Connect Python to a MySQL database
• Write and execute an UPDATE query
• Handle responses and exceptions

Let’s dive in!

Prerequisites

Before you begin, make sure you have:

• Python installed
• MySQL Server running
• mysql-connector-python installed

You can install the MySQL connector with:

pip install mysql-connector-python

Step 1: Connect to MySQL Database

import mysql.connector

mydb = mysql.connector.connect(
    host="localhost",
    user="your_username",
    password="your_password",
    database="your_database"
)

This code sets up a connection to your MySQL database. Replace the values with your actual credentials.

Step 2: Write the Update Query

Let’s say you want to update a user’s email where the id is 1:

mycursor = mydb.cursor()

sql = "UPDATE users SET email = %s WHERE id = %s"
val = ("newemail@example.com", 1)

mycursor.execute(sql, val)
mydb.commit()

print(mycursor.rowcount, "record(s) updated")

Explanation:

• UPDATE users – This targets the users table.
• SET email = %s – We’re updating the email column.
• WHERE id = %s – Ensures only the row with id = 1 is updated.
• execute(sql, val) – Safely executes the query with parameters.
• commit() – Saves changes to the database.

Step 3: Add Error Handling (Optional but Recommended)

try:
    mycursor = mydb.cursor()
    sql = "UPDATE users SET email = %s WHERE id = %s"
    val = ("newemail@example.com", 1)
    mycursor.execute(sql, val)
    mydb.commit()
    print(mycursor.rowcount, "record(s) updated successfully")
except mysql.connector.Error as err:
    print("Error:", err)
finally:
    mydb.close()

Adding try-except-finally ensures your app doesn’t crash if something goes wrong.

Real-World Example Use Cases

• Update user profiles
• Change product prices
• Modify order statuses
• Reset passwords

Final Tips

• Always use placeholders (%s) to avoid SQL injection.
• Call .commit() after any change (INSERT/UPDATE/DELETE).
• Use .rowcount to know how many rows were affected.