P06SQLIntermediateInterpret12 min

Customers With No Orders

Find customers without purchases using a left join and null logic.

#left join#null#retention

Scenario

The onboarding team wants to reach customers who signed up but have never placed an order.

Problem statement

Return customers with no matching row in the orders table.

Your Task

  1. Start from all customers.
  2. Keep unmatched rows after joining.
  3. Test for a nullable value from the orders table.

Tables

customers(customer_id, customer_name) orders(order_id, customer_id, amount)

Related Concepts

SQL joinsNULL semanticsCustomer activation

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