WHERE clause - Python MySQL

Welcome to another tutorial on Python MySQL. Here you learn about the WHERE clause; how to filter rows from the fetched result-set or delete a specific row from a MySQL table as well as updating a specific row using the WHERE clause.

However, the WHERE clause is simply a way to provide a condition or multiple conditions to the SQL engine, that is used on the query result-set to filter out the required records of data.

Python MySQL WHERE Clause

The WHERE Clause was used previously. Such as the Update Table Data, and Delete Table on Python MySQL.

When there is a need to select data from a table based on a specified condition, the WHERE clause in the SELECT statement can be used. Check out the features below:

The WHERE clause is typically used for filtering the rows from the result-set.
Also, it is crucial in fetching, updating, and deleting data from the MySQL Table.

Below is the general syntax of using the WHERE clause in the SELECT statement:

SELECT column_name
FROM table_name
WHERE condition;

Using WHERE Clause

Check out the example below, where we will fetch the row having rollno=2 from our student's table in our previous tutorial on Create table.

import mysql.connector as mysql
###First create a connection between mysql and python
db = mysql.connect(
    host = "localhost",
    user = "yourusername",
    passwd = "yourpassword",
    database = "studytonight"
)
# now create a cursor object on the connection object 
# created above by using cursor() method
cursor = db.cursor()

## defining the Query
query = "SELECT * FROM students WHERE rollno= 2"

## getting records from the table
cursor.execute(query)

## fetching all records from the 'cursor' object
records = cursor.fetchall()

## Showing the data
for record in records:
    print(record)

Output:

('Ada Chang', 'Computer Science', 'Hong Kong', 2)