You have two tables.

The customers table knows who people are. Name, city, contact details.

The orders table knows what they bought. Product, amount, date.

Neither table alone answers the question: which customers in Mumbai spent more than 50,000 rupees last month?

You need both tables combined through their shared key. That combination is a join.

Joins are where SQL becomes genuinely powerful. The ability to link tables that were designed separately and query them as if they were one is what makes relational databases so useful for data analysis.

The Setup

import sqlite3 import pandas as pd

conn = sqlite3 . connect ( " joins_practice.db " )

conn .…