Left Outer Join Retention

How do we retain all customers including those who have never placed an order using a left join?

Intermediate⏱ 2 Minutes⭐ 420 XP

🤔 THE QUESTION

How do we retain all customers including those who have never placed an order using a left join?

💡 WHAT IS IT?

customers.join(orders, 'customer_id', 'left') preserves every customer row, filling missing order fields with NULL.

🎯 WHAT IS IT USED FOR?

Customer retention analysis, identifying non-purchasing leads, and comprehensive user reporting.

💻 EXAMPLE

joined_df = customers.join(orders, "customer_id", "left")

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